Question

2X+B_2H_6->[BH_2]^+[BH_4]^-

The amine X can be?

• (CH_3)_3N
• (CH_3)_2NH
• (CH_3)NH_2
• None

Solution

CH_3 is an electron releasing group or we can say it has +I effect. So the electron density over N atom increases and its tendency to donate increases.

So as the number of methyl groupds attached to the N increases the tendency of N to release electron increases.

But in the case where 3, methyl groups are attached to N the steric hinderance is significant and reducing the chance of (CH_3)_3N to react with diborane.