/ Preparation Chemistry NCERT Exemplar Solutions Class 11th Chapter Five
- States of Matter Multiple Type Questions
- States of Matter Short Answer Type Questions
- States of Matter Matching Type Questions
- States of Matter Assertion and Reason Type Questions
- States of Matter Multiple Choice Type Questions
- States of Matter Long Answer Type Questions
- JEE MAINS 5 July
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States of Matter Multiple Type Questions
| 1. A person living in Shimla observed that cooking food without using pressure cooker takes more time. The reason for this observation is that at high altitude: (i) Pressure increases (ii) Temperature decreases (iii) Pressure decreases (iv) Temperature increases |
| Ans: option (iii) pressure decreases At high altitude the pressure is low and therefore, water boils at lower temperature because the vapour pressure becomes equal to atmospheric temperature at low temperature due to which the food takes more time to be cooked without using a pressure cooker. |
| 2. Which of the following property of water can be used to explain the spherical shape of rain droplets? (i) Viscosity (ii) Ssurface tension (iii) Critical phenomena (iv) Pressure |
| Ans: option (ii) surface tension Surface tension minimises the surface area of the liquid and at minimum surface area, the liquid is in its lowest energy state and hence most stable. Spherical shape of rain droplets has minimum surface area due to surface tension. |
Commonly asked questions
A person living in Shimla observed that cooking food without using pressure cooker takes more time. The reason for this observation is that at high altitude:
(i) Pressure increases
(ii) Temperature decreases
(iii) Pressure decreases
(iv) Temperature increases
This is a multiple choice answer as classified in NCERT Exemplar
Option (iii) pressure decreases
At high altitude the pressure is low and therefore, water boils at lower temperature because the vapour pressure becomes equal to atmospheric temperature at low temperature due to which the food takes more time to be cooked without using a pressure cooker.
Which of the following property of water can be used to explain the spherical shape of rain droplets?
(i) Viscosity
(ii) Surface tension
(iii) Critical phenomena
(iv) Pressure
This is a multiple choice answer as classified in NCERT Exemplar
option (ii) surface tension
Surface tension minimises the surface area of the liquid and at minimum surface area, the liquid is in its the lowest energy state and hence most stable. Spherical shape of rain droplets has minimum surface area due to surface tension.
A plot of volume (V) versus temperature (T) for a gas at constant pressure is a straight line passing through the origin. The plots at different values of pressure are shown in Fig. 5.1. Which of the following order of pressure is correct for this gas?
(i) p1 > p2 > p3 > p4
(ii) p1 = p2 = p3 = p4
(iii) p1 < p2 < p3 < p4
(iv) p1 < p2 = p3 < p4
This is a multiple choice answer as classified in NCERT Exemplar
option iii. p1 < p2 < p3 < p4
At a particular temperature, PV is constant
Therefore, V ∝
So, as v1 > v2 > v3 > v4 the order of pressure: p1 < p2 < p3 < p4 .
The interaction energy of London force is inversely proportional to sixth power of the distance between two interacting particles but their magnitude depends upon
(i) Charge of interacting particles
(ii) Mass of interacting particles
(iii) Polarisability of interacting particles
(iv) Strength of permanent dipoles in the particles.
This is a multiple choice answer as classified in NCERT Exemplar
option (iii) polarisability of interacting particles.
The energy of the London force or London dispersion force is inversely proportional to (distance between two interacting particles)6 but their magnitude depends upon the polarisability of interacting particles.
Dipole-dipole forces act between the molecules possessing permanent dipole. Ends of dipoles possess ‘partial charges’. The partial charge is
(i) More than unit electronic charge
(ii) Equal to unit electronic charge
(iii) Less than unit electronic charge
(iv) Double the unit electronic charge
This is a multiple choice answer as classified in NCERT Exemplar
option (iii) less than unit electronic charge
Charge of 1 electron is 1.6 × 10 -19 C and the partial charge is always less than the unit electronic charge.
The pressure of a 1:4 mixture of dihydrogen and dioxygen enclosed in a vessel is one atmosphere. What would be the partial pressure of dioxygen?
(i) 0.8 × 10 5 atm
(ii) 0.008 Nm-2
(iii) 8 ×104 Nm-2
(iv) 0.25 atm
This is a multiple choice answer as classified in NCERT Exemplar
option (iii) 8 × 104 Nm-2
Partial pressure of oxygen, Po2= Xo2 Ptotal
Mole fraction of O2=
= =
Po2= 1 = (?Ptotal = 1 atm)
1 atm = 1.1034 × 105 Nm-2 or Pa
Partial pressure of dioxygen = 0.8 ×105 = 8×104 Nm-2
As the temperature increases, average kinetic energy of molecules increases. What would be the effect of increase of temperature on pressure provided the volume is constant?
(i) Increases
(ii) Decreases
(iii) Remains same
(iv) Becomes half
This is a multiple choice answer as classified in NCERT Exemplar
Option (i) increases
Gay Lussac’s law shows the direct relationship between the pressure and the temperature of a fixed amount of gas at constant volume.
Gay Lussac's law states that at constant volume, the pressure of a fixed amount of a gas is directly proportional to the temperature.
Therefore,
P∝T ……….at constant volume
Thus, pressure increases if the temperature is increased at a constant volume.
To elaborate more on this topic, we will see a real-life example.
Gases possess characteristic critical temperature which depends upon the magnitude of intermolecular forces between the particles. Following are the critical temperatures of some gases.
|
Gases |
Critical temperature in Kelvin |
|
H2 |
33.2 |
|
He |
5.3 |
|
O2 |
154.3 |
|
N2 |
126 |
From the above data what would be the order of liquefaction of these gases? Start writing the order from the gas liquefying first
(i) H2, He, O2, N2
(ii) He, O2, H2, N2
(iii) N2, O2, He, H2
(iv) O2, N2, H2, He
This is a multiple choice answer as classified in NCERT Exemplar
Option (iv) O2, N2, H2, He
Higher the critical temperature of gases more easily, the gas will be liquefied. So, the order of liquefying of gases will be O2 > N2 > H2 >He.
What is SI unit of viscosity coefficient (η)?
(i) Pascal
(ii) Nsm-2
(iii) km-2s
(iv) Nm-2
This is a multiple choice answer as classified in NCERT Exemplar
option (ii) Nsm-2
viscosity coefficient (η) =
SI unit of (η)= Nsm-2
Atmospheric pressures recorded in different cities are as follows
|
Cities |
p in N/m2 |
|
Shimla |
1.01×105 |
|
Bangalore |
1.2×105 |
|
Delhi |
1.02×105 |
|
Mumbai |
1.21×105 |
Consider the above data and mark the place at which liquid will boil first.
(i) Shimla
(ii) Bangalore
(iii) Delhi
(iv) Mumbai
This is a multiple choice answer as classified in NCERT Exemplar
option (i). Shimla
The temperature at which the liquid boils when the vapour pressure becomes equal to the atmospheric pressure is known as the boiling point of the liquid. When the atmospheric pressure is low, the boiling point of the liquid will be low. As Shimla has the lowest atmospheric pressure, it will boil first.
Which curve in Fig. 5.2 represents the curve of ideal gas?
(i) B only
(ii) C and D only
(iii) E and F only
(iv) A and B only
This is a multiple choice answer as classified in NCERT Exemplar
Option (i). B only
For all ideal gas PV = constant. Only B has no change with the change in PV, so only line B represents the curve of ideal gas.
Increase in kinetic energy can overcome intermolecular forces of attraction. How will the viscosity of liquid be affected by the increase in temperature?
(i) Increase
(ii) No effect
(iii) Decrease
(iv) No regular pattern will be followed
This is a multiple choice answer as classified in NCERT Exemplar
Option (iii) Decrease
The increase in temperature increases the kinetic energy which can overcome intermolecular forces of attraction due to which the viscosity decreases and the liquid starts flowing.
How does the surface tension of a liquid vary with increase in temperature?
(i) Remains same
(ii) Decreases
(iii) Increases
(iv) No regular pattern is followed
This is a multiple choice answer as classified in NCERT Exemplar
Option (ii). Decreases
When the temperature increases, kinetic energy of the molecule increases which leads to decrease in the intermolecular forces and hence, decreases the surface tension.
In the following questions two or more options may be correct.
With regard to the gaseous state of matter which of the following statements are correct?
(i) Complete order of molecules
(ii) Complete disorder of molecules
(iii) Random motion of molecules
(iv) Fixed position of molecules
This is a multiple choice answer as classified in NCERT Exemplar
Option (ii). Complete disorder of molecules and
(iii). Random motion of molecules
In a gaseous state of matter, molecules are arranged in complete disorder and they move in random motion in all directions.
Which of the following figures does not represent 1 mole of dioxygen gas at STP?
(i) 16 grams of gas
(ii) 22.7 litres of gas
(iii) 6.022 × 1023 dioxygen molecules
(iv) 11.2 litres of gas
This is a multiple choice answer as classified in NCERT Exemplar
Option (i). 16 grams of gas and
(iv). 11.2 litres of gas
1 mole of dioxygen at STP occupies = 22.4 L
molar mass of dioxygen = 32 g
contain 6.023×1023 molecules of oxygen gas
Under which of the following two conditions applied together a gas deviates most from the ideal behaviour?
(i) Low pressure
(ii) High pressure
(iii) Low temperature
(iv) High temperature
This is a multiple choice answer as classified in NCERT Exemplar
option (ii). High pressure and
(iii). Low temperature
The real gases obey the ideal gas equation, PV= nRT at low pressure and high temperature. So, a gas does not obey the ideal gas equation or behave ideally at high pressure and low temperature.
Which of the following changes decrease the vapour pressure of water kept in a sealed vessel?
(i) Decreasing the quantity of water
(ii) Adding salt to water
(iii) Decreasing the volume of the vessel to one-half
(iv) Decreasing the temperature of water
This is a multiple choice answer as classified in NCERT Exemplar
Option (ii). Adding salt to water and
(iv). Decreasing the temperature of water
By adding salt to water, the water molecule available at the surface to evaporate will be low and hence, the vapour pressure decreases. Also vapour pressure is directly proportional to temperature so when we decrease the temperature of water the vapour pressure decreases.
States of Matter Short Answer Type Questions
| 1. If 1 gram of each of the following gases are taken at STP. which of the gases will occupy (a) greatest volume and (b) smallest volume ? CO, H2O, CH4, NO |
| Ans: (a) greatest volume is occupied by CH4 and (b) smallest volume by NO According to Avagadro’s Law, Volume of 1 mole of a gas at STP = 22.4 L Now , we know, 1 mole = Molar mass ∴ Volume of 28g mol-1 of CO at STP = 22.4 L So, Volume of 1 g of CO at STP = 22.4 L / 28 g mol-1 Similarly, Volume of 1 g of H2O at STP = 22.4 L / 18 g mol-1 Volume of 1 g of CH4 at STP = 22.4 L / 16 g mol-1 (Greatest volume) Volume of 1 g of NO at STP = 22.4 L / 30 g mol-1 (smallest volume) |
| 2. Physical properties of ice, water and steam are very different. What is the chemical composition of water in all the three states. |
| Ans: Physical state of ice, water and steam are very different but the chemical composition of water in all the three states is H2O. |
Commonly asked questions
If 1 gram of each of the following gases are taken at STP. which of the gases will occupy
(a) greatest volume and
(b) smallest volume ?
CO, H2O, CH4, NO
This is a short answer type question as classified in NCERT Exemplar
(a) the greatest volume is occupied by CH4 and
(b) the smallest volume by NO
According to Avagadro’s Law,
Volume of 1 mole of a gas at STP = 22.4 L
Now, we know,
1 mole = Molar mass
∴ Volume of 28g mol-1 of CO at STP = 22.4 L
So, Volume of 1 g of CO at STP = 22.4 L / 28 g mol-1
Similarly,
Volume of 1 g of H2O at STP = 22.4 L / 18 g mol-1
Volume of 1 g of CH4 at STP = 22.4 L / 16 g mol-1 (the greatest volume)
Volume of 1 g of NO at STP = 22.4 L / 30 g mol-1 (the smallest volume)
Physical properties of ice, water and steam are very different. What is the chemical composition of water in all the three states.
This is a short answer type question as classified in NCERT Exemplar
Physical state of ice, water and steam are very different but the chemical composition of water in all the three states is H2O.
The behaviour of matter in different states is governed by various physical laws. According to you what are the factors that determine the state of matter?
This is a short answer type question as classified in NCERT Exemplar
The factors that determine the states of matter are:
1. Temperature
2. Pressure
3. Mass and volume
Use the information and data given below to answer the questions (a) to (c):
• Stronger intermolecular forces result in higher boiling point.
• Strength of London forces increases with the number of electrons in the molecule.
• Boiling point of HF, HCl, HBr and HI are 293 K, 189 K, 206 K and 238 K respectively.
(a) Which type of intermolecular forces are present in the molecules HF, HCl, HBr and HI?
(b) Looking at the trend of boiling points of HCl, HBr and HI, explain out of dipole-dipole interaction and London interaction, which one is predominant here
(c) Why is boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?
This is a short answer type question as classified in NCERT Exemplar
(a) HCl, HBr and HI have dipole-dipole and london dispersion interaction whereas HF has hydrogen bonding in addition (due to the high electronegativity of the F atom).
(b) The electronegativity decreases from Cl, Br and I so the dipole-dipole interaction will also decrease as HCl > HBr > HI and it is contrary to the boiling point order which is HCl < HBr < HI. This confirms that the London interaction is predominant.
(c) F atom has the highest electronegativity so it has hydrogen bonding interaction in addition to dipole-dipole and london dispersion interaction which leads to the highest boiling point of HF whereas HCl has the lowest boiling point because london force plays the predominant role in boiling point than dipole-dipole interaction and london force increases proportionally with the molecular weight of the compound. HCl has the lowest molecular weight among HCl, HBr and HI therefore it has the least london force interaction which leads to the lowest boiling point
What will be the molar volume of nitrogen and argon at 273.15 K and 1 atm?
This is a short answer type question as classified in NCERT Exemplar
The molar volume of both nitrogen and argon at 273.15 K and 1 atm is 22.4 L.
At STP (1 atm pressure and 273.15 K or 00 C), the molar volume i.e the volume of 1 mole gas is 22.4L.
A gas that follows Boyle’s law, Charle’s law and Avogadro’s law is called an ideal gas. Under what conditions a real gas would behave ideally?
This is a short answer type question as classified in NCERT Exemplar
A gas that follows Boyle's law, Charle's law and Avogadro's law is called an ideal gas.
Real gas behaves ideal under low pressure and high temperature. Under these conditions, the intermolecular interactions are minimum.
Two different gases ‘A’ and ‘B’ are filled in separate containers of equal capacity under the same conditions of temperature and pressure. On increasing the pressure slightly the gas ‘A’ liquefies but gas B does not liquify even on applying high pressure until it is cooled. Explain this phenomenon.
This is a short answer type question as classified in NCERT Exemplar
On increasing the pressure slightly the gas 'A' liquefies but gas B does not liquify even on applying high pressure until it is cooled at same conditions of temperature and pressure filled in equal capacity containers it happens because the gas ‘A’ being at the critical temperature liquifies on slightly increasing the pressure and gas ’B’ being at higher temperature than critical temperature does not liquifies even on applying high pressure until it is cooled.
Value of universal gas constant (R) is same for all gases. What is its physical significance?
This is a short answer type question as classified in NCERT Exemplar
Unit of R depends on the units of p, V and T are measured, We know, R=
One of the assumptions of kinetic theory of gases states that “there is no force of attraction between the molecules of a gas.” How far is this statement correct? Is it possible to liquefy an ideal gas? Explain.
This is a short answer type question as classified in NCERT Exemplar
The assumption of the kinetic theory of gases which states that- “ there is no force of attraction between the molecules of a gas. ” is a correct statement. Ideal gas has minimum force of attraction between the molecules and hence, it cannot be liquified. Liquefaction of a gas can only be done when the force of attraction between the molecules increases, which is not possible for an ideal gas.
The magnitude of surface tension of liquid depends on the attractive forces between the molecules. Arrange the following in increasing order of surface tension : water, alcohol (C2H5OH) and hexane [CH3(CH2)4CH3].
This is a short answer type question as classified in NCERT Exemplar
Water and alcohol are polar molecules which have high electronegative O atm so they have hydrogen bonding along with dipole-dipole interaction. Hexane is a nonpolar molecule that has London dispersion force which is a weak force between the molecules. Water has stronger H-bonding than alcohol. So, the order of attractive force will be:
Hexane < Alcohol < Water
More attractive forces between the molecules, the greater the magnitude of surface tension of the liquid.
Pressure exerted by saturated water vapour is called aqueous tension. What correction term will you apply to the total pressure to obtain pressure of dry gas?
This is a short answer type question as classified in NCERT Exemplar
The gas collected over water, is moist and has saturated water vapour that exerts pressure which is known as aqueous tension. So the total pressure of the gas will be:
Pmoist gas = P dry gas + Aqueous Tension
∴ PDry gas = P moist gas - Aqueous Tension or
PDry gas = P Total - Aqueous Tension
So, the correction term you apply to the total pressure to obtain pressure of dry gas is P Total - Aqueous Tension.
Name the energy which arises due to motion of atoms or molecules in a body. How is this energy affected when the temperature is increased?
This is a short answer type question as classified in NCERT Exemplar
The energy which arises due to motion of atoms or molecules in a body is known as thermal energy and the average kinetic energies of all the molecules increases with increases in temperature.
Name two intermolecular forces that exist between HF molecules in liquid state.
This is a short answer type question as classified in NCERT Exemplar
The two intermolecular forces that exist between HF molecules in liquid state are hydrogen bonding (as F is a highly electronegative atom) and dipole-dipole interaction (as HF is a polar molecule).
One of the assumptions of kinetic theory of gases is that there is no force of attraction between the molecules of a gas. State and explain the evidence that shows that the assumption is not applicable for real gases.
This is a short answer type question as classified in NCERT Exemplar
The assumption of kinetic theory of gases that there is no force of attraction between the molecules of a gas is applicable for real gases. The evidence for this is that the real gas can be liquified at high pressure and low temperature. This proves that there is force of attraction between the molecules of gas.
Compressibility factor, Z, of a gas is given as Z=
(i) What is the value of Z for an ideal gas?
(ii) For real gas what will be the effect on value of Z above Boyle’s temperature?
This is a short answer type question as classified in NCERT Exemplar
(i) The value of Z for an ideal gas is 1.
(ii) For real gas, the value of Z > 1 above Boyle's temperature
The critical temperature (Tc) and critical pressure ( pc) of CO2 are 30.98°C and 73 atm respectively. Can CO2 (g) be liquefied at 32°C and 80 atm pressure?
This is a short answer type question as classified in NCERT Exemplar
The CO2 gas cannot be liquified at the 32°C and 80 atm pressure as the given temperature and pressure are above critical temperature (Tc) and critical pressure (pc) which are 30.98°C and 73 atm respectively.
For real gases the relation between p, V and T is given by van der Waals equation:
where 'a' and are van der Waals constants, 'nb' is approximately equal to the total volume of the molecules of a gas.
'a' is the measure of magnitude of intermolecular attraction.
I. Arrange the following gases in the increasing order of 'b'. Give reason. O2, CO2, H2, He
II. Arrange the following gases in the decreasing order of magnitude of ‘a’. Give reason. CH4, O2, H2.
This is a short answer type question as classified in NCERT Exemplar
I.The increasing order of ‘b’ of the given gases is:
H2 < He < O2 < CO2
Volume of a gas is proportional to the size of the molecule.
II.The decreasing order of magnitude of ‘a’ of the given molecule is:
CH4 > O2 > H2
The Van there waals constant ‘a’ represents the magnitude of intermolecular attraction which increases with increase in the size of the electron cloud of the molecule. So the greater the size of a molecule, greater will be the electron cloud and hence greater will be the polarizability and more will be the magnitude of intermolecular attraction.
The relation between pressure exerted by an ideal gas (pideal) and observed pressure (preal) is given by the equation:
If pressure is taken in Nm-2, number of moles in mol and volume in m3, Calculate the unit of 'a'.
What will be the unit of 'a' when pressure is in atmosphere and volume in dm3?
This is a short answer type question as classified in NCERT Exemplar
Unit of ‘P’ = N m-2
Unit of ‘a’ = N m-2 X (m3)2 / (mol)2
= N-m4 mol-2
Unit of ‘a’ when pressure is in atm, and volume in dm3
Unit of ‘P’ = atm
Unit of ‘a’ = atm X (dm3)2 / (mol)2
= atm-dm6 mol-2
Name two phenomena that can be explained on the basis of surface tension.
This is a short answer type question as classified in NCERT Exemplar
The two phenomena that can be explained on the basis of surface tension are:
1. Spherical shape of rain droplets.
2. Capillary action due to which the liquid in capillary rises and falls.
Viscosity of a liquid arises due to strong intermolecular forces existing between the molecules. Stronger the intermolecular forces, greater is the viscosity. Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also give reason for the assigned order in one line.
Water, hexane (CH3CH2CH2CH2CH2CH3), glycerine (CH2OH CH(OH) CH2OH) .
This is a short answer type question as classified in NCERT Exemplar
Hexane is a nonpolar molecule which has london force between the molecules, which is a weak force.
Water and glycerine have O atoms which is an electronegative atom that forms H bonding between the molecules along with dipole-dipole interaction.
Glycerine has three O atoms, so it forms more H bonding and hence, has stronger intermolecular forces.
So the increasing order of intermolecular forces is Hexane < Water < Glycerin. Stronger the intermolecular forces, the greater is the viscosity, so the increasing order of their viscosities is:
Hexane < Water < Glycerin
Explain the effect of increasing the temperature of a liquid, on intermolecular forces operating between its particles, what will happen to the viscosity of a liquid if its temperature is increased?
This is a short answer type question as classified in NCERT Exemplar
The increase in temperature increases the kinetic energy of the molecules which decreases the intermolecular forces operating between its particles and hence, the viscosity of a liquid decreases. So, the viscosity of a liquid decreases if its temperature is increased.
The variation of pressure with volume of the gas at different temperatures can be graphically represented as shown in Fig. 5.3.
On the basis of this graph answer the following questions.
1. How will the volume of a gas change if its pressure is increased at constant temperature?
2. At a constant pressure, how will the volume of a gas change if the temperature is increased from 200K to 400K?
This is a short answer type question as classified in NCERT Exemplar
1. According to Boyle's law,
Pressure of a gas is inversely proportional to volume of gas at constant temperature. So, the volume decreases with increase in pressure at constant temperature.
2. According to Charles's law,
Volume of a gas is directly proportional to temperature when the pressure is constant. So, the volume of gas increases with increase in temperature.
Pressure versus volume graph for a real gas and an ideal gas are shown in Fig. 5.4.
Answer the following questions on the basis of this graph.
1. Interpret the behaviour of real gas with respect to ideal gas at low pressure.
2. Interpret the behaviour of real gas with respect to ideal gas at high pressure.
3. Mark the pressure and volume by drawing a line at the point where real gas behaves as an ideal gas.
This is a short answer type question as classified in NCERT Exemplar
1. At low pressure, the curve of real gas coincides with that of ideal gas, this shows that the deviation of behaviour of real gas with respect to ideal gas is small or negligible.
2. At high pressure, the curve of real gas is far apart from ideal gas, this shows that the deviation of behaviour of real gas with respect to ideal gas is large.
3. The pressure p1 and volume V1 are the point where real gas behaves as an ideal gas.
States of Matter Matching Type Questions
| 1. Match the graphs between the following variables with their names :
|
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| Ans:
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| 2. Match the following gas laws with the equation representing them.
|
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| Ans:
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Commonly asked questions
Match the graphs between the following variables with their names :
|
Graphs |
Names |
|
(i) Pressure vs temperature (a) graph at constant molar volume. |
(a) Isotherms |
|
(ii) Pressure vs volume graph at constant temperature. |
(b) Constant temperature curve |
|
(iii) Volume vs temperature graph at constant pressure. |
(c) Isochores |
|
|
(d) Isobars |
This is a matching answer type question as classified in NCERT Exemplar
(i) Pressure vs temperature (a) graph at constant molar volume. | (c) Isochores |
(ii) Pressure vs volume graph at constant temperature. | (a) Isotherms |
(iii) Volume vs temperature graph at constant pressure. | (d) Isobars |
Match the following gas laws with the equation representing them.
|
(i) Boyle’s law |
(a) V ∝ n at constant T and p |
|
(ii) Charle’s law |
(b) ptotal = p1 + p2 + p3……… at constant T, V |
|
(iii) Dalton's law |
(c) = constant |
|
(iv) Avogadro law |
(d) V ∝ T at constant n and p |
|
(e) p ∝ at constant n and T |
This is a matching answer type question as classified in NCERT Exemplar
(i) Boyle’s law | (e) p ∝ at constant n and T |
(ii) Charle’s law | (d) V ∝ T at constant n and p |
(iii) Dalton's law | (b) ptotal = p1 + p2 + p3……… at constant T, V |
(iv) Avogadro law | (a) V ∝ n at constant T and p |
Match the following graphs of ideal gas with their co-ordinates:
|
Graphical representation |
x and y co-ordinates |
|
(i)  |
(a) pV vs. V |
|
(ii)  |
(b) p vs. V |
|
(iii) |
(c) p vs. |
This is a matching answer type question as classified in NCERT Exemplar
(i) - B
(ii) - C
(iii) - A
States of Matter Assertion and Reason Type Questions
| In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question. 1. Assertion (A): Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules. Reason (R): Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart. (i) Both A and R are true and R is the correct explanation of A. (ii) Both A and R are true but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A is false but R is true. |
| Ans: option (i). Both A and R are true and R is the correct explanation of A. |
| Assertion (A): At constant temperature, pV vs V plot for real gases is not a straight line. Reason (R) : At high pressure all gases have Z > 1 but at intermediate pressure most gases have Z < 1. (i) Both A and R are true and R is the correct explanation of A. (ii) Both A and R are true but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A is false but R is true. |
| Ans: At constant temperature, the pV vs V plot for real gases is not a straight line because there is intermolecular attraction present in real gases which is absent in ideal gases; hence ideal gases form a straight line in the pV vs V plot at constant temperature. |
Commonly asked questions
In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.
Assertion (A): Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules.
Reason (R): Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
This is a assertion and reason answer type question as classified in NCERT Exemplar
option (i). Both A and R are true and R is the correct explanation of A.
Assertion (A): At constant temperature, pV vs V plot for real gases is not a straight line.
Reason (R) : At high pressure all gases have Z > 1 but at intermediate pressure most gases have Z < 1.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
This is a assertion and reason answer type question as classified in NCERT Exemplar
At constant temperature, the pV vs V plot for real gases is not a straight line because there is intermolecular attraction present in real gases which is absent in ideal gases; hence ideal gases form a straight line in the pV vs V plot at constant temperature.
Assertion (A): The temperature at which vapour pressure of a liquid is equal to the external pressure is called boiling temperature.
Reason (R) : At high altitude atmospheric pressure is high.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
This is a assertion and reason answer type question as classified in NCERT Exemplar
option (iii). A is true but R is false.
At high altitude, the atmospheric pressure is low.
Assertion (A): Gases do not liquefy above their critical temperature, even on applying high pressure.
Reason (R) : Above critical temperature, the molecular speed is high and intermolecular attractions cannot hold the molecules together because they escape because of high speed.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
This is a assertion and reason answer type question as classified in NCERT Exemplar
(i) Both A and R are true and R is the correct explanation of A.
Assertion (A): At critical temperature liquid passes into gaseous state imperceptibly and continuously.
Reason (R) : The density of liquid and gaseous phase is equal to critical temperature.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
This is a assertion and reason answer type question as classified in NCERT Exemplar
(i) Both A and R are true and R is the correct explanation of A.
Assertion (A): Liquids tend to have maximum number of molecules at their surface.
Reason (R) : Small liquid drops have spherical shape.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
This is a assertion and reason answer type question as classified in NCERT Exemplar
States of Matter Multiple Choice Type Questions
| 1. A person living in Shimla observed that cooking food without using pressure cooker takes more time. The reason for this observation is that at high altitude: (i) Pressure increases (ii) Temperature decreases (iii) Pressure decreases (iv) Temperature increases |
| Ans: Option (iii) pressure decreases At high altitude the pressure is low and therefore, water boils at lower temperature because the vapour pressure becomes equal to atmospheric temperature at low temperature due to which the food takes more time to be cooked without using a pressure cooker. |
| 2. Which of the following property of water can be used to explain the spherical shape of rain droplets? (i) Viscosity (ii) Surface tension (iii) Critical phenomena (iv) Pressure |
| Ans: Option (ii) surface tension Surface tension minimises the surface area of the liquid and at minimum surface area, the liquid is in its lowest energy state and hence most stable. Spherical shape of rain droplets has minimum surface area due to surface tension. |
| 3. A plot of volume (V) versus temperature (T) for a gas at constant pressure is a straight line passing through the origin. The plots at different values of pressure are shown in Fig. 5.1. Which of the following order of pressure is correct for this gas? (i) p1 > p2 > p3 > p4 (ii) p1 = p2 = p3 = p4 (iii) p1 < p2 < p3 < p4 (iv) p1 < p2 = p3 < p4 
|
| Ans: Optioniii. p1 < p2 < p3 < p4 At a particular temperature, PV is constant Therefore, V ∝ So, as v1 > v2 > v3 > v4 the order of pressure: p1 < p2 < p3 < p4 . |
| 4. The interaction energy of London force is inversely proportional to sixth power of the distance between two interacting particles but their magnitude depends upon (i) Charge of interacting particles (ii) Mass of interacting particles (iii) Polarisability of interacting particles (iv) Strength of permanent dipoles in the particles. |
| Ans: Option (iii) polarisability of interacting particles. The energy of the London force or London dispersion force is inversely proportional to (distance between two interacting particles)6 but their magnitude depends upon the polarisability of interacting particles. |
| 6. The pressure of a 1:4 mixture of dihydrogen and dioxygen enclosed in a vessel is one atmosphere. What would be the partial pressure of dioxygen? (i) 0.8 × 10 5 (ii) 0.008 Nm-2 (iii) 8 ×104 Nm- (iv) 0.25 atm |
| Ans: Option (iii) 8 × 104 Nm-2 Partial pressure of oxygen, Po2= Xo2 Ptotal Mole fraction of O2= = = Po2= 1 = (∵Ptotal = 1 atm) 1 atm = 1.1034 × 105 Nm-2 or Pa Partial pressure of dioxygen = 0.8 ×105 = 8×104 Nm-2 |
| 7. As the temperature increases, average kinetic energy of molecules increases. What would be the effect of increase of temperature on pressure provided the volume is constant? (i) Increases (ii) Decreases (iii) Remains same (iv) Becomes half |
| Ans: Option (i) increases Gay Lussac’s law shows the direct relationship between the pressure and the temperature of a fixed amount of gas at constant volume. Gay Lussac's law states that at constant volume, the pressure of a fixed amount of a gas is directly proportional to the temperature. Therefore, P∝T ………..at constant volume Thus, pressure increases if the temperature is increased at a constant volume. To elaborate more on this topic, we will see a real-life example. |
| 8. Gases possess characteristic critical temperature which depends upon the magnitude of intermolecular forces between the particles. Following are the critical temperatures of some gases.
From the above data what would be the order of liquefaction of these gases? Start writing the order from the gas liquefying first (i) H2, He, O2, N2 (ii) He, O2, H2, N2 (iii) N2, O2, He, (iv) O2, N2, H2, He |
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| Ans: Option (iv) O2, N2, H2, He Higher the critical temperature of gases more easily, the gas will be liquefied. So, the order of liquefying of gases will be O2 > N2 > H2 >He. |
| 9. What is SI unit of viscosity coefficient (η)? (i) Pascal (ii) Nsm-2 (iii) km-2s (iv) Nm-2 |
| Ans: Option (ii) Nsm-2 viscosity coefficient (η) = SI unit of (η) = Nsm-2 |
| 10. Atmospheric pressures recorded in different cities are as follows
Consider the above data and mark the place at which liquid will boil first. 1. Shimla 2. Bangalore 3. Delhi 4. Mumbai |
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| Ans: Option (i). Shimla The temperature at which the liquid boils when the vapour pressure becomes equal to the atmospheric pressure is known as the boiling point of the liquid. When the atmospheric pressure is low, the boiling point of the liquid will be low. As Shimla has the lowest atmospheric pressure, it will boil first. |
| 11. Which curve in Fig. 5.2 represents the curve of ideal gas? 
(i) B only (ii) C and D only (iii) E and F only (iv) A and B only |
| Ans: Option (i). B only For all ideal gas PV = constant. Only B has no change with the change in PV, so only line B represents the curve of ideal gas. |
| 12. Increase in kinetic energy can overcome intermolecular forces of attraction. How will the viscosity of liquid be affected by the increase in temperature? (i) Increase (ii) No effect (iii) Decrease (iv) No regular pattern will be followed |
| Ans: Option (iii) Decrease The increase in temperature increases the kinetic energy which can overcome intermolecular forces of attraction due to which the viscosity decreases and the liquid starts flowing. |
| 13. How does the surface tension of a liquid vary with increase in temperature? (i) Remains same (ii) Decreases (iii) Increases (iv) No regular pattern is followed |
| Ans: Option (ii). Decreases When the temperature increases, kinetic energy of the molecule increases which leads to decrease in the intermolecular forces and hence, decreases the surface tension. |
| In the following questions two or more options may be correct. 14. With regard to the gaseous state of matter which of the following statements are correct? (i) Complete order of molecules (ii) Complete disorder of molecules (iii) Random motion of molecules (iv) Fixed position of molecules |
| Ans: Option (ii). Complete disorder of molecules and (iii). Random motion of molecules In a gaseous state of matter, molecules are arranged in complete disorder and they move in random motion in all directions. |
| 15. Which of the following figures does not represent 1 mole of dioxygen gas at STP? (i) 16 grams of gas (ii) 22.7 litres of gas (iii) 6.022 × 1023 dioxygen molecules (iv) 11.2 litres of gas |
| Ans: Option (i). 16 grams of gas and (iv). 11.2 litres of gas 1 mole of dioxygen at STP occupies = 22.4 L molar mass of dioxygen = 32 g contain 6.023×1023 molecules of oxygen gas |
| 16. Under which of the following two conditions applied together a gas deviates most from the ideal behaviour? (i) Low pressure (ii) High pressure (iii) Low temperature (iv) High temperature |
| Ans: option (ii). High pressure and (iii). Low temperature The real gases obey the ideal gas equation, PV= nRT at low pressure and high temperature. So, a gas does not obey the ideal gas equation or behave ideally at high pressure and low temperature. |
| 17. Which of the following changes decrease the vapour pressure of water kept in a sealed vessel? (i) Decreasing the quantity of water (ii) Adding salt to water (iii) Decreasing the volume of the vessel to one-half (iv) Decreasing the temperature of water |
| Ans: option (ii). Adding salt to water and (iv). Decreasing the temperature of water By adding salt to water, the water molecule available at the surface to evaporate will be low and hence, the vapour pressure decreases. Also vapour pressure is directly proportional to temperature so when we decrease the temperature of water the vapour pressure decreases. |
States of Matter Long Answer Type Questions
| 1. Isotherms of carbon dioxide at various temperatures are represented in Fig. 5.5. Answer the following questions based on this figure. 
i. In which state will CO2 exist between the points a and b at temperature T1? ii. At what point will CO2 start liquefying when temperature is T1? iii. At what point will CO2 be completely liquefied when temperature is T2? iv. Will condensation take place when the temperature is T3. v. What portion of the isotherm at T1 represents liquid and gaseous CO2 at equilibrium? |
| Ans. i. CO2 will exist in a gaseous state between the points a and b at temperature T1. ii. At point b, CO2 will start liquefying when temperature is T1 iii. At point g, CO2 will be completely liquefied when temperature is T2 iv. No, the condensation will not take place when the temperature is T3 because T3 > Tc. v. Between b and c of the isotherm at T1 , represents the liquid and gaseous CO2 at equilibrium. |
| 2. The variation of vapour pressure of different liquids with temperature is shown in Fig. 5.6. 
i. Calculate graphically boiling points of liquids A and B. ii. If we take liquid C in a closed vessel and heat it continuously. At what temperature will it boil? |
| Ans: i. The boiling points of liquid A is approximately 315 K and of liquid B is approximately 345 K (shown below graphically). 
ii. Liquid C in a closed vessel will not boil as the pressure keeps on increasing. |
Commonly asked questions
Isotherms of carbon dioxide at various temperatures are represented in Fig. 5.5. Answer the following questions based on this figure.
i. In which state will CO2 exist between the points a and b at temperature T1?
ii. At what point will CO2 start liquefying when temperature is T1?
iii. At what point will CO2 be completely liquefied when temperature is T2?
iv. Will condensation take place when the temperature is T3.
v. What portion of the isotherm at T1 represents liquid and gaseous CO2 at equilibrium?
This is a long answer type question as classified in NCERT Exemplar
i. CO2 will exist in a gaseous state between the points a and b at temperature T1.
ii. At point b, CO2 will start liquefying when temperature is T1
iii. At point g, CO2 will be completely liquefied when temperature is T2
iv. No, the condensation will not take place when the temperature is T3 because T3 > Tc.
v. Between b and c of the isotherm at T1 , represents the liquid and gaseous CO2 at equilibrium.
The variation of vapour pressure of different liquids with temperature is shown in Fig. 5.6.
i. Calculate graphically boiling points of liquids A and B.
ii. If we take liquid C in a closed vessel and heat it continuously. At what temperature will it boil?
This is a long answer type question as classified in NCERT Exemplar
i. The boiling points of liquid A is approximately 315 K and of liquid B is approximately 345 K (shown below graphically).
ii. Liquid C in a closed vessel will not boil as the pressure keeps on increasing.
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Commonly asked questions
The total number of coordination sites in ethylenediaminetetraacetate ( EDTA ??) is
(Coordination)
The minimum number of moles of O₂ required for complete combustion of 1 mole of propane and 2 moles of butane is
C? H? + 5O? → 3CO? + 4H? O
C? H? + (13/2)O? → 4CO? + 5H? O
∴ 2 mol C? H? is given
∴ 13 mol O? is required for combustion of Butane
∴ Total mol of O? = 5 + 13 = 18
An oxidation - reduction in which 3 electrons are transferred has a ∆Gº of 17.37 kJ mol⁻¹ at 25°C. The value of E°cell (in V is _ × 10⁻²)(1 F = 96,500Cmol⁻¹)
ΔG° = –nFE°
∴ 17.37 x 10³ = –3 x 96500 x E°
∴ E° = –6 x 10? ² V
The number of chiral carbon(s) present in peptide, lie-Arg-Pro, is
The structure of the given compound is as show below
A soft drink was bottled with a partial pressure of CO? of 3 bar over the liquid at room temperature. The partial pressure of CO? over the solution approaches a value of 30bar when 44 g of CO? is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is × 10?¹ /
(First dissociation constant of H?CO? = 4.0 × 10??; log 2 = 0.3; density of the soft drink = 1 g mL?¹)
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Chemistry NCERT Exemplar Solutions Class 11th Chapter Five Exam
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