The ionic equation shows calcium atoms reacting with hydrogen ions to form calcium ions and hydrogen.
Ca+2H+→Ca2++H2\text{Ca} + 2\text{H}^{+} \rightarrow \text{Ca}^{2+} + \text{H}_2Ca+2H+→Ca2++H2
Which half equation shows the reduction that takes place in this reaction?
2H+→H2+2e−2\text{H}^{+} \rightarrow \text{H}_2 + 2\text{e}^{-}2H+→H2+2e−
Ca→Ca2++2e−\text{Ca} \rightarrow \text{Ca}^{2+} + 2\text{e}^{-}Ca→Ca2++2e−
2H++2e−→H22\text{H}^{+} + 2\text{e}^{-} \rightarrow \text{H}_22H++2e−→H2
Ca2++2e−→Ca\text{Ca}^{2+} + 2\text{e}^{-} \rightarrow \text{Ca}Ca2++2e−→Ca
86 exam-style questions on AQA GCSE Chemistry 4.1 Reactivity of metals, covering 4.1.1 Metal oxides, 4.1.2 The reactivity series, 4.1.3 Extraction of metals and reduction, and 4.1.4 Oxidation and reduction in terms of electrons. Each one has a worked solution and a mark scheme showing where the marks go.