Question

-2. The percent yield for the following reaction carried out in carbon tetrachloride (CCL) solution is 80%
Br2 + Cl2 → 2Brci
(a) How many moles of BrCl is formed from the reaction of 0.025 mol Br2 and 0.025 mol CL?
(b) How many moles of Br2 is left unreacted?​

Answer 1

(a) 0.0416 moles of BrCl is formed from the reaction of 0.025 moles of Br₂ and 0.025 moles of Cl.

(b) 0.005 moles of Br₂ is left unreacted.

Explanation:

(a) The chemical equation of the reaction given in the question is:

Br₂ + Cl₂ → 2 BrCl

1 mole of Br₂ = 1 mole of Cl₂

Br₂ = 0.025 × 2 × 79.909 = 4 g  

Cl₂ = 0.025 × 2 × 35.453 = 1.773 g

The total mass = 5.773 g which is 100% yield.

From question, we need 80% which is:

0.80 × 5.773 = 4.62 g

Number of moles of BrCl is:

Moles = 4.62/110.98 = 0.0416 moles

(b) In every reaction, one moles Br₂ is used.

0.04 ÷ 2 = 0.02 moles Br is used.

Therefore, 0.025 - 0.02 = 0.005 moles of Br₂ is left.