DP Chemistry (last assessment 2024)

Question 20N.2.sl.TZ0.b(ii)

b(ii).

[Maximum mark: 2]

20N.2.sl.TZ0.b(ii)

Chlorine undergoes many reactions.

$2.67 g$ of manganese(IV) oxide was added to $200.0 {cm}^{3}$ of $2.00 mol {dm}^{- 3} HCl$ .

${MnO}_{2} (s) + 4 HCl (aq) \to {Cl}_{2} (g) + 2 H_{2} O (l) + {MnCl}_{2} (aq)$

Determine the limiting reactant, showing your calculations.

[2]

Markscheme

$« n_{HCl} = 2.00 mol {dm}^{- 3} \times 0.2000 {dm}^{3} » = 0.400 mol$ ✔

$« \frac{0.400}{4} = » 0.100 mol$ AND ${MnO}_{2}$ is the limiting reactant ✔

Accept other valid methods of determining the limiting reactant in M2.

Examiners report

It was pleasing that the majority of the candidates were able to determine the limiting reactant by using the stoichiometric ratio.

Syllabus sections