A borane (X) is reacted with ammonia to give a salt of borohydride (Y). The $^{11}\mathrm{B}$ NMR spectrum of Y consists of a triplet and a quintet. The borane X is
(a)$\mathrm{B}_{2} \mathrm{H}_{6}$
(b)$\mathrm{B}_{3} \mathrm{H}_{9}$
(c)$\mathrm{B}_{4} \mathrm{H}_{8}$
(d)$\mathrm{B}_{5} \mathrm{H}_{9}$
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
B₂H₆ + 2NH₃ → [BH₂(NH₃)₂]⁺[BH₄]⁻: the BH₄⁻ boron is a quintet (4 H) and the BH₂ boron a triplet (2 H).