Question

Complete the following reactions and balance them:

1. B + H2So4 (concentrated )-----

2. LiBH4 + H2o ---------

Answer 1

1) Boron will be oxidized with concentrated sulfuric acid up to boric acid formation:

B + H₂SO₄ = H₃BO₃ + SO₂ + H₂O

SO₄^2- + 4H⁺ + 2e = SO₂ + 2H₂O

B + 3H₂O - 3e = BO₃^3- + 6H⁺

Thus,

2B + 3H₂SO₄ = 3SO₂ + 2H₃BO₃

2) Lithium tetrahydroborate will be completely hydrolised and the products will react to form lithium borate and hydrogen gas:

LiBH₄ + 2H₂O = LiBO₂ + 4H₂