Displacement reactions involving the halogens

2 marks · Easy

A student adds excess bromine water to 0.050 mol of potassium iodide solution. Calculate the maximum amount (in mol) of iodine that can be formed.

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0.025 mol (±0.001)

Also accept: 2 significant figures

Common mistakes: Answering 0.05 mol; Not dividing by 2

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Marking points

M1 · 1 mark · Use 2KI(aq) + Br2(aq) -> 2KBr(aq) + I2(aq) to set up correct ratio: 2 mol KI forms 1 mol I2.

A1 · 1 mark · Final answer: 0.025 mol I2.

Worked solution

Mole ratio KI:I2 is 2:1. So 0.050 mol KI would give mol I2: mol.