Question

For the reactions: NaBH$_4$ + I$_2$ $\rightarrow$ A + NaI + H$_2$, and A + LiH $\rightarrow$ B, what are A and B, respectively? (Reactions are not balanced)

• A. B$_2$H$_6$, LiBH$_4$
• B. B$_2$H$_6$, (BN)$_x$
• C. BH$_3$, CO, LiBH$_4$
• D. BH$_3$, CO, B$_3$N$_3$H$_6$

Hint:

Identify products of inorganic reactions by recognizing common synthesis pathways. NaBH$_4$ with I$_2$ often forms B$_2$H$_6$, and B$_2$H$_6$ with LiH forms LiBH$_4$.

Answer 1

The Correct Option is A

First reaction: NaBH$_4$ + I$_2$ $\rightarrow$ A + NaI + H$_2$.
NaBH$_4$ reacts with I$_2$ to form diborane (B$_2$H$_6$).
The balanced reaction is: 2NaBH$_4$ + I$_2$ $\rightarrow$ B$_2$H$_6$ + 2NaI + H$_2$.
So, A = B$_2$H$_6$.
Second reaction: A + LiH $\rightarrow$ B.
B$_2$H$_6$ + 2LiH $\rightarrow$ 2LiBH$_4$.
So, B = LiBH$_4$.
Thus, A = B$_2$H$_6$, B = LiBH$_4$.