JEE Challenger
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ChemEasyAdv 2015 • Paper 2

Moles of Boron Containing Product from Reaction of Diborane with Methanol

When three moles of B2H6\text{B}_2\text{H}_6 are reacted completely with methanol, determine the number of moles of the boron-containing product that is formed.

Official Numerical Answer6

Topics & Concepts

p-Block Elementsp-Block ElementsStoichiometry

Step-by-Step Solution

Diborane (B2H6\text{B}_2\text{H}_6) reacts with alcohols such as methanol (CH3OH\text{CH}_3\text{OH}) to undergo alcoholysis, forming a trialkyl borate and releasing hydrogen gas.

The balanced chemical equation for the reaction of diborane with methanol is: B2H6+6 CH3OH⟶2 B(OCH3)3+6 H2\text{B}_2\text{H}_6 + 6\,\text{CH}_3\text{OH} \longrightarrow 2\,\text{B}(\text{OCH}_3)_3 + 6\,\text{H}_2

Here, the boron-containing product formed is trimethyl borate, B(OCH3)3\text{B}(\text{OCH}_3)_3.

From the stoichiometry of the balanced equation:

  • 1 mole of B2H6 yields 2 moles of B(OCH3)31\text{ mole of }\text{B}_2\text{H}_6 \text{ yields } 2\text{ moles of }\text{B}(\text{OCH}_3)_3.

Therefore, when 3 moles of B2H63\text{ moles of }\text{B}_2\text{H}_6 are reacted completely: Moles of B(OCH3)3=3×2=6 moles\text{Moles of }\text{B}(\text{OCH}_3)_3 = 3 \times 2 = 6\text{ moles}

Thus, the number of moles of the boron-containing product formed is 66.

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