According to VESPR theory repulsion order

  lp - lp > lp - bp > bp - bp

As the number of lone pairs of electrons increases, bond angle decreases due to repulsion between lp-lp, Moreover, as the electronegativity of central atom decreases, bond angle decreases.

The correct order of increasing bond angle is Cl₂O < ClO₂^- < ClO₂

In ClO₂^- there are 2 Ione pairs of electrons present on the central chlorine atom. Therefore the bond angle in ClO₂^- is less than 118° which is the bond angle in ClO₂ which has less number of electrons on chlorine. 

Option b is correct  because as the charge increases covalent character also increases.

p_x-p_x and p_y-p_y will form pi bond when z-axis is molecular axis as the options have only one of these so option (d) is the correct answer.

Li⁺ have larger size in aq.solution due to the presence of the water molecules present inside the solution surronds easily and become the solution to be more hydrated comparing to the corresponding element present in the aqeous solution.

Ionisation Potential is directly proportional to positive oxidation state and inversely proportional to negative oxidation state.So, in O^2- removal of electron is easiest.

On moving down the group, there is an increase in the size of atoms. As a result, the tendency to accept an additional electron decreases and hence, the electron gain enthalpy decreases from Ne to Rn. However, He has small size and much higher tendency to accept an additional electron. Hence, its electron gain enthalpy is least positive of all the noble gases. 

Thus, it is concluded that neon has the highest positive electrons gain enthalpy.

Actually electron gain enthalphy and ionisation energy both are dependent on electronic configuration.

Electronegativity means tendency to attract electron it doesnot matter where it will keep the electron

Electron gain entalphy basically refer to attract e it must have space to keep electron in sub shell like spdf should be present order of electronegativity is

F > O > N > Cl > Br  > I > S > C > P

With respect to Chlorine hydrogen will be electropositive. Chlorine being a strong electronegative element tends to force hydrogen to loss electron and hydrogen acquire electropositive character so that chlorine can complete its octet .

Francium has the greatest tendency to lose electrons.

37 = Rb

55 = Cs

87 = Fr

All belong to alkali metal group.

So answer is (d)