A Level Chemistry 2017 Paper 1 Question 17 Solution - Exclusive

In this exclusive video we want to discuss the suggested solution for A Levels Chemistry (H2 Chemistry) 2017 Paper 1 Question 17.

Let's take a look at this question:

2017 A Level H2 Chem P1 Q17 question

The topic tested in this question is on Electrochemistry. In particular the concept of electrolysis and calculation of products discharged during electrolysis.

We first need to deduce the products formed at the anode and cathode.

The reaction at the cathode is already given in the question where acrylonitrile is reduced.

For the reaction at the anode, water will be oxidised to form O2.

2017 A Level H2 Chem P1 Q17 half equations

Since 0.01 mol of acrylonitrile is electrolysed, we can use the reduction half equation to compare mole ratio between electron and acrylonitrile to determine the number of moles of electrons gained at the cathode is 0.01 mol.

Since the electrolysis is the same redox reaction,

mol of electrons lost at the anode = mol of electrons gained at cathode = 0.01 mol

2017 A Level H2 Chem P1 Q17 electron lost equal electron gain

We can then compare mole ratio between O2 and electron to determine the number of moles of O2 produced is 2.5 x 10-3 mol.

Finally we can work out volume of O2 at room temperature and pressure by multiplying mol of O2 with molar volume at r.t.p. (24.0 dm3)

2017 A Level H2 Chem P1 Q17 volume calculation

Therefore the answer to this question is A.

Check out this video for the full solution and detailed explanation!

Topic: Electrochemistry, Physical Chemistry, A Level Chemistry, Singapore

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