How intermolecular forces are broken during evaporation?

If the intermolecular forces are weak, then molecules can break out of the solid or liquid more easily into the gas phase. Consider two different liquids, one polar one not, contained in two separate boxes. We would expect the molecules to more easily break away from the bulk for the non-polar case. If the molecules are held tightly together by strong intermolecular forces, few of the molecules will have enough kinetic energy to separate from each other. They will stay in the liquid phase, and the rate of evaporation will be low. ... They will escape from the liquid phase, and the rate of evaporation will be high. To make water evaporate, energy has to be added. The water molecules in the water absorb that energy individually. Due to this absorption of energy the hydrogen bonds connecting water molecules to one another will break.

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when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.