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Edexcel IGCSE Chemistry 1.60C electrolysis practical

Practise electrolysis-practical questions by plotting syringe data, identifying anomalies and explaining gas-volume relationships.

Syllabus
First assessment 2019
Course
Chemistry 4CH1

Exam points

  • Plot gas-volume results, draw a straight best-fit line through the origin and circle anomalies.
  • Deduce the current-volume relationship from syringe data for gases produced in electrolysis.
  • Explain lower chlorine volumes using solubility or gas loss rather than a reading error.

1.60C Electrolysis practical question 1

[Maximum number: 7]

Question (a)

(a)

The teacher uses this apparatus to investigate the electrolysis of a solution of dilute hydrochloric acid.

The ammeter measures the current.

Figure for Question (a) — Edexcel IGCSE Chemistry


The teacher wants to find out if there is a relationship between current and volume of gas collected at each electrode.

She adjusts the power supply until the current is 0.1 amp.
After 5 minutes she records the volume of gas collected in syringe X and syringe Y.
The teacher repeats the experiment several times, using a different current each time.

The table gives the teacher's results for syringe Y.

Table for Question (a) — Edexcel IGCSE Chemistry
[ 6 ]

Question (i)

(i)

Plot the results for syringe Y.

[ 1 ]

Question (ii)

(ii)

Draw a circle around the anomalous result.

[ 1 ]

Question (iii)

(iii)

Draw a line of best fit.

Figure for Question (iii) — Edexcel IGCSE Chemistry
[ 1 ]

Question (iv)

(iv)

Explain a possible cause of the anomalous result, other than misreading the apparatus.

[ 2 ]

Question (v)

(v)

Deduce the relationship between current and volume of gas collected in syringe Y .

[ 1 ]

Question (b)

(b)

The ionic half-equation for the reaction that produces the gas in syringe X is

2Cl−→Cl2+2e−2 \mathrm{Cl}^{-} \rightarrow \mathrm{Cl}_{2}+2 \mathrm{e}^{-}

The ionic half-equation for the reaction that produces the gas in syringe Y is

2H++2e−→H22 \mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{H}_{2}
[ 1 ]

Question (i)

(i)

Suggest why the volume of chlorine collected in syringe X is always less than the volume of hydrogen collected in syringe Y.

[ 1 ]
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