Calcium hydride, CaH2\text{CaH}_2CaH2, is an ionic compound. When molten, it can be electrolysed to yield calcium metal and hydrogen gas.
Which equation represents the reaction occurring at the anode during the electrolysis of molten calcium hydride?
Ca2++2e−→Ca\text{Ca}^{2+} + 2\text{e}^- \rightarrow \text{Ca}Ca2++2e−→Ca
2H++2e−→H22\text{H}^+ + 2\text{e}^- \rightarrow \text{H}_22H++2e−→H2
2H−−2e−→H22\text{H}^- - 2\text{e}^- \rightarrow \text{H}_22H−−2e−→H2
4OH−−4e−→O2+2H2O4\text{OH}^- - 4\text{e}^- \rightarrow \text{O}_2 + 2\text{H}_2\text{O}4OH−−4e−→O2+2H2O
34 exam-style questions on OCR GCSE Chemistry Electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.