Question

Identify the correct statements from the following
I. $B _{2} H _{6}$ is an electron deficient hydride.
II. $NH _{3}$ an electron rich hydride.
III. $NaH$ is a covalent hydride.
IV. $YbH _{2.55}$ is an interstitial hydride.

• A. I, II, II
• B. II, III, IV
• C. I, II, IV
• D. I, III, IV

Answer 1

Answer: (C)

(I) $B _{2} H _{6}$ (diborane) is an electron deficient hydride. This can be explained on the basis of structure given below.



(II) $NH _{3}$ is electron rich hydride due to presence of lone pair of electrons.



(III) $NaH$ is an ionic hydride, generally hydride of alkali metals are ionic.
Hence, statement $III$ is incorrect.

(IV) $YbH _{2.55}$ is an interstitial hydride. Here, smaller atom like hydrogen present in interstitial space of $Yb$ metal. Hence, it forms interstitial hydride.