Chemistry 0620 · IGCSE · Electrolysis

Electrolysis — practice question

Hydrogen may be produced from methane through steam reforming. $\text{CH}_4(g) + \text{H}_2\text{O}(g) \rightleftharpoons \text{CO}(g) + 3\text{H}_2(g)$ This reaction is performed with a nickel catalyst at temperatures from 700 ^{\circ}C to 1100 ^{\circ}C and at a pressure of one atmosphere. The forward reaction is endothermic, meaning heat is absorbed.
(a)[2]

What does the term catalyst mean?

(b)[2]

Suggest two reasons why a temperature below 700 ^{\circ}C is not chosen.

(c)[1]

Suggest one advantage of using a pressure above one atmosphere.

(d)[1]

Suggest one disadvantage of using a pressure above one atmosphere.

(e(i))[2]

Define electrolysis.

(e(ii))[1]

Name one substance that can be used for the inert electrodes.

(e(iii))[1]

Write an ionic half-equation for the reaction that produces hydrogen.

(e(iv))[1]

Where in the electrolytic cell is hydrogen produced?

(e(v))[2]

Describe a test that can be used for chlorine. test result

(f)[2]

The electrolysis of concentrated aqueous sodium chloride is shown by the following word equation. sodium chloride + water → sodium hydroxide + hydrogen + chlorine Construct a chemical equation to represent this reaction. Do not include state symbols.

(g)[3]

State one use for chlorine, sodium hydroxide and hydrogen.

Worked solution & mark scheme

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