Chemistry NCERT Exemplar Solutions Class 11th Chapter Five

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? 

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? 

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.

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.

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.

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.

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.

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.

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.

Match the following gas laws with the equation representing them.