The correct statements from the following are :

A. Ionic radii of trivalent cations of group 13 elements decreases down the group.

B. Electronegativity of group 13 elements decreases down the group.

C. Among the group 13 elements, Boron has highest first ionisation enthalpy.

D. The trichloride and triiodide of group 13 elements are covalent in nature.

Choose the correct answer from the options given below :

Identify the molecule $(X)$ with maximum number of lone pairs of electrons (obtained using Lewis dot structure) among $\mathrm{HNO}_3, \mathrm{H}_2 \mathrm{SO}_4, \mathrm{NF}_3$ and $\mathrm{O}_3$. Choose the correct bond angle made by the central atom of the molecule $(X)$.

From the given following (A to D) cyclic structures, those which will not react with Tollen's reagent are:

The correct sequence of reagents for the above conversion of X to Y is :