Chemistry · May / June 2021 · Paper 42 · Question 4
0620
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The question as text
A student carries out an electrolysis experiment using the apparatus shown. + – carbon electrodes wire dilute aqueous sodium chloride The student uses dilute aqueous sodium chloride.
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4(a)[1]
electrolyte
4(b)(i)[2]
4OH– → 2H2O + O2 + 4e–
balance of charge (1)
rest of equation (1)
4(b)(ii)[1]
(OH–(aq) ions) lose electrons
4(c)[1]
fizzing
4(d)[2]
2H+ + 2e– → H2
species correct (1)
fully correct equation (1)
4(e)(i)[2]
fizzing (1)
green gas (1)
4(e)(ii)[2]
(litmus turns) blue and alkali / base forms (1)
Sodium hydroxide / NaOH (forming) (1)
4(f)[1]
platinum
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