Question

Which one of the following molecular hydrides acts as a Lewis acid?

• A. $NH_3$
• B. $H_2$O
• C. $B_2H_6$
• D. $CH_4$

Answer 1

Answer: (C)

$B_2H_6$

Answer 2

Electron deficient molecules $t$ as Lewis acid. Among the given molecules, only diborane is electron deficient, i.e. does not have complete octet . Thus, it acts as a Lewis acid. $NH_3 \, and \, H_2O$ being electron rich molecules behave as Lewis base.