The electrolysis of molten compounds
3 marks · EasyThe table below shows the ions present in three molten ionic compounds:
| Compound | Ions present |
|---|---|
| A: MgF_2 | |
| B: KCl | |
| C: CaBr_2 |
For compound B, name the product formed at the anode.
For compound C, write the half-equation for the reaction at the cathode.
For compound A, state the formula of the ion that gains electrons at the cathode.
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) Chlorine
(b)
(c)
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Marking points
B1 (a) · 1 mark · States chlorine as the product at the anode in molten KCl; accept Cl_2.
B1 (b) · 1 mark · Correct half-equation for Ca^{2+} ions: .
B1 (c) · 1 mark · States as the ion gaining electrons at the cathode in MgF_2.
Worked solution
a) Compound B (KCl): At the anode, chloride ions give chlorine gas: Cl_2.
b) Compound C (CaBr_2): At the cathode, .
c) Compound A (MgF_2): The cation gaining electrons is .