Electrolysis and redox
4 marks · NormalYou are asked to explain how the OILRIG mnemonic helps when deciding whether a reaction is oxidation or reduction.
Write what each letter in OILRIG stands for.
Use the mnemonic to decide whether the following process is oxidation or reduction: Fe^{2+} gains 2 electrons to form Fe.
State how the mnemonic helps you to answer part (b).
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) OILRIG stands for Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).
(b) Reduction.
(c) Because Fe^{2+} gains electrons, and OILRIG says 'Reduction Is Gain', it is reduction.
Common mistakes: Not linking gain/loss of electrons to reduction/oxidation.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Writes Oxidation Is Loss (of electrons).
B1 (a) · 1 mark · Writes Reduction Is Gain (of electrons).
A1 (b) · 1 mark · Correctly identifies process as reduction.
M1 (c) · 1 mark · Explains application of OILRIG: gain of electrons means reduction.
Worked solution
a. OILRIG: Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).
b. Reduction.
c. The mnemonic shows that since Fe^{2+} gains electrons, the process is reduction.