Questions

( int t ; t = a, a = b, b = t ;);

This code won't compile since declaration of t cannot occur within parentheses.

Chemical Compounds with stronger intermolecular forces have higher boiling points.

The order of strengths of intermolecular forces is:

 London dispersion < dipole-dipole < H-bonding

${\text{Methane (CH}}_{\mathrm{4)}}$ — London dispersion forces

${\text{Dimethyl ether (CH}}_3{\text{OCH}}_{\mathrm{3)}}$ — dipole-dipole attractions

${\text{Methanol (CH}}_3\text{OH)}$ — hydrogen bonding

Therefore, ${\text{Methanol -}}^{}$${\text{CH}}_3\text{OH}$$\text{with H-Bonding have highest Boiling Point among the given chemical compounds.}$

It is to overcome this opposite frictional force , that  we have to apply the needed force to make the body move

In dealing with a coil spring the spring constant will depend on the stiffness of the spring material, the thicknessof the wire from which the spring is wound and, diameterof the turns of the coil, the number of turns per unit length and the overall length of the spring.

"The moon smiled at me" is the example of personification in the given options.

Personification is a technique in which we give objects human traits like emotions, gestures, speech,... by using metaphor. 

Here moon is an object which cannot smile but using metaphor sense, we gave that sense to it.