Class 11th

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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.

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.

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=pVnT  Now, let's say, the  pressure is measured in Pascal, per mole volume is measured in m³ and temperature is measured in Kelvin,   then. Units of 'R' are Pa m³K^-1 mol^-1. Also, R is work done per mole per kelvin. It's unit is J K^-1 mol^-1 (Joule is the unit of work done).

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.

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.

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. 

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

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.