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Question 18N.2.hl.TZ0.1d

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Date November 2018 Marks available [Maximum mark: 2] Reference code 18N.2.hl.TZ0.1d
Level hl Paper 2 Time zone TZ0
Command term State Question number d Adapted from N/A
d.
[Maximum mark: 2]
18N.2.hl.TZ0.1d

3.26 g of iron powder are added to 80.0 cm3 of 0.200 mol dm−3 copper(II) sulfate solution. The following reaction occurs:

Fe (s) + CuSO4 (aq) → FeSO4 (aq) + Cu (s)

(d)

A student electrolyzed aqueous iron(II) sulfate, FeSO4 (aq), using platinum electrodes. State half-equations for the reactions at the electrodes, using section 24 of the data booklet.

[2]

Markscheme

Anode (positive electrode):

2H2O (l) → O2 (g) + 4H+ (aq) + 4e– ✔

 

Cathode (negative electrode):

2H2O (l) + 2e– → H2 (g) + 2OH– (aq)
OR
2H+ (aq) + 2e– → H2 (g) ✔

 

Accept “4OH– (aq) → O2 (g) + 2H2O (l)  + 4e–” OR “Fe2+ (aq) → Fe3+ (aq) + e–” for M1.

Accept “Fe2+ (aq) + 2e– → Fe (s)” OR “SO42- (aq) 4H+ (aq) + 2e– → 2H2SO3(aq) + H2O (l)”
for M2.

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