Question

Among $Ca{H}_2,N{H}_3,NaH$ and $B_2{H}_6,$ which are covalent hydride?

• A. $N{H}_3$ and $B_2{H}_6$
• B. $NaH$ and $Ca{H}_2$
• C. $NaH$ and $N{H}_3$
• D. $Ca{H}_2$ and $B_2{H}_6$

Answer 1

Answer: (A)

Hydrides are binary compounds of hydrogen. These can be classified in four groups viz :
(i) Ionic hydrides e.g., $NaH,Ca{H}_2,LiHetc.$
(ii) Covalent hydrides e.g., $B_2{H}_6,N{H}_3,Sb{H}_{3}etc.$
(iii) Polynuclear hydrides e.g., $LiAl{H}_4,NaB{H}_{4}etc.$
(iv) Interstitial hydrides, in which hydrogen is trapped in the interstial spaces of transition metals.