Consider the following statements:

(A) NF₃ molecule has a trigonal planar structure.

(B) Bond length of $\mathrm{N}_{2}$ is shorter than $\mathrm{O}_{2}$.

(C) Isoelectronic molecules or ions have identical bond order.

(D) Dipole moment of $\mathrm{H}_{2}\mathrm{S}$ is higher than that of water molecule.

Choose the correct answer from the options given below:

In the above conversion the correct sequence of reagents to be added is

Which of the following expressions is correct in case of a $\mathrm{CsCl}$ unit cell (edge length 'a')?

'A' formed in the above reaction is