A student checks three statements about a precipitation reaction and electron transfer.
Statement 1: When silver nitrate solution reacts with sodium chloride solution, the Na+\text{Na}^{+}Na+ ions and NO3−\text{NO}_3^{-}NO3− ions are cancelled when the ionic equation is formed.
Statement 2: The half equation 2H+→H2+2e−2\text{H}^{+} \rightarrow \text{H}_2 + 2\text{e}^{-}2H+→H2+2e− represents hydrogen ions forming hydrogen gas.
Statement 3: The half equation 2O2−→O2+4e−2\text{O}^{2-} \rightarrow \text{O}_2 + 4\text{e}^{-}2O2−→O2+4e− represents oxide ions forming oxygen gas.
Which statements are correct?
1 only
2 only
1 and 2 only
1 and 3 only
134 exam-style questions on OCR GCSE Chemistry 3.1 Introducing chemical reactions, covering 3.1.1 Writing formulae and balanced chemical equations, 3.1.2 Formulae of compounds from ions, and state symbols, 3.1.3 Conservation of mass and observed changes in mass, 3.1.4 Half equations and balanced ionic equations, 3.1.5 The mole and the Avogadro constant, and 3.1.6 Stoichiometry, limiting reactants and reacting masses. Each one has a worked solution and a mark scheme showing where the marks go.