Gases expand and occupy all the space available to them. Which of the following assumption explain this behaviour correctly?

In which of the following solid substance dispersion forces exist?

Three types of potential energy due to attractive interaction between two species $\mathrm{X}$ and $\mathrm{Y}$ are represented by the curves $\mathrm{I}, \mathrm{II},$ and $\mathrm{III}$ in the figure below.

 
Consider the dominating interaction between non-rotating species $(\mathrm{X}\dots \mathrm{Y})$ for $\mathrm{X}={\mathrm{Na}}^{+},{\left({\mathrm{CH}}_3\right)}_2\mathrm{CO}$, ${\mathrm{C}}_6{\mathrm{H}}_6,{\mathrm{CH}}_4$ and $\mathrm{Y}={\left({\mathrm{CH}}_3\right)}_2\mathrm{CO},{\mathrm{Cl}}^{-},{\mathrm{C}}_2{\mathrm{H}}_6,{\mathrm{CHCl}}_3$. The correct assignment of the $\mathrm{X}$... $\mathrm{Y}$ interactions

to the types $\mathrm{I},\mathrm{II}$, and $\mathrm{III}$ is:

Match the type of interaction in column $\mathrm{A}$ with the distance dependence of their interaction energy in column $\mathrm{B}:$

Increasing order of boiling points in the following compounds is:

$\underset{\left(\mathrm{i}\right)}{{\mathrm{CH}}_3\mathrm{COOH}} \underset{\left(\mathrm{ii}\right)}{ {\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CHO}} \underset{\left(\mathrm{iii}\right)}{{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{OH}} \underset{\left(\mathrm{iv}\right)}{{\mathrm{CH}}_3{\mathrm{COCH}}_3}$

Intermolecular forces are forces of attraction and repulsion between interacting particles that will include :

A. dipole-dipole forces.
B. dipole-induced dipole forces.
C. hydrogen bonding.
D. covalent bonding.
E. dispersion forces.

Choose the most appropriate answer from the options given below: