The numbers of lines shown by the $\mathrm{BH}_{3}$ part of the molecule $\mathrm{Ph}_{3} \mathrm{P} .{ }^{11} \mathrm{BH}_{3}$ in the ${ }^{1} \mathrm{H}$ and ${ }^{11} \mathrm{B}$ NMR spectra are, respectively $\left[\mathrm{I}\left({ }^{11} \mathrm{B}\right)=3 / 2 ; \mathrm{I}\left({ }^{31} \mathrm{P}\right)=1 / 2\right]$
(a)8 and 8
(b)4 and 8
(c)3 and 6
(d)6 and 3
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
BH₃ protons: coupled to ¹¹B (I = 3/2, 4 lines) and ³¹P (2) → 8 lines; ¹¹B: coupled to 3 H (4 lines) and ³¹P (2) → 8 lines.