Question

What are \( X \) and \( Y \) respectively in the following reactions?

X → _CO B₂H₆ → _NaH → _(C2H5)2O Y

Options:

• (1) BH₃, 2CO; NaBO₂
• (2) BH₃, CO; NaBH₄
• (3) BH₃, CO; NaBO₂
• (4) BH₃, CO; Na₂B₄O₇

• A. \( BH_3, 2CO; NaBO_2 \)
• B. \( BH_3, CO; NaBH_4 \)
• C. \( BH_3, CO; NaBO_2 \)
• D. \( BH_3, CO; Na_2B_4O_7 \)

Hint:

Borane (\( BH_3 \)) is a key reagent in boron chemistry and forms diborane (\( B_2H_6 \)) upon dimerization. Sodium borohydride (\( NaBH_4 \)) is commonly used as a reducing agent in organic synthesis.

Answer 1

The Correct Option is B

Step 1: Understanding the Reaction Sequence 
The given reaction sequence involves a series of transformations starting from \( X \) and leading to \( Y \). Let's analyze the stepwise reactions:
1. The first reaction suggests that \( X \) reacts with carbon monoxide (\( CO \)) to form diborane (\( B_2H_6 \)). This indicates that \( X \) is borane (\( BH_3 \)), which is a well-known precursor to diborane formation.
2. Diborane (\( B_2H_6 \)) then reacts with sodium hydride (\( NaH \)), leading to the formation of sodium borohydride (\( NaBH_4 \)).
3. The presence of diethyl ether (\( (C_2H_5)_2O \)) as a solvent helps stabilize the final product.
 

Step 2: Evaluating the Given Options 
- Option (1): Incorrect as it suggests \( X = BH_3, 2CO \), which is not required for diborane formation.
- Option (2): Correct as it correctly identifies \( X = BH_3 \) and \( Y = NaBH_4 \).
- Option (3): Incorrect as it wrongly identifies \( Y \) as sodium metaborate (\( NaBO_2 \)).
- Option (4): Incorrect as it suggests \( Y = Na_2B_4O_7 \), which does not match the reaction sequence.
Thus, the correct answer is 

Option (2).