Displacement reactions involving solutions of salts
4 marks · NormalWhen manganese metal is placed in a solution of iron(II) sulfate, a displacement reaction occurs.
State the oxidising agent in this reaction.
State the reducing agent in this reaction.
Explain why manganese is the reducing agent in terms of electron transfer.
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(a) Fe^{2+}(aq)
(b) Mn(s)
(c) Manganese atoms lose electrons to iron(II) ions. By giving electrons, manganese reduces Fe^{2+} ions and is itself oxidised.
Common mistakes: Mixing up agent roles
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Marking points
B1 (a) · 1 mark · Identifies Fe^{2+}(aq) as the oxidising agent.
B2 (b) · 1 mark · Identifies Mn(s) as the reducing agent.
B3 (c) · 2 marks · Explains that manganese gives electrons to iron(II) ions, reducing them and being oxidised itself. 1 mark for saying Mn gives electrons, 1 mark for connection to reduction of Fe^{2+}.
Worked solution
a) The oxidising agent is Fe^{2+}(aq).
b) The reducing agent is Mn(s).
c) Manganese transfers electrons to Fe^{2+} ions. By doing this, manganese causes iron(II) to be reduced (gain electrons), and so manganese is acting as the reducing agent (and is itself oxidised as it loses electrons).