A student adds sodium carbonate solution to an unknown transition metal aquo ion solution. The student observes vigorous effervescence alongside the formation of a green precipitate.
Which transition metal aquo ion was present in the original solution?
[Fe(H2O)6]2+[\text{Fe}(\text{H}_2\text{O})_6]^{2+}[Fe(H2O)6]2+
[Cr(H2O)6]3+[\text{Cr}(\text{H}_2\text{O})_6]^{3+}[Cr(H2O)6]3+
[Fe(H2O)6]3+[\text{Fe}(\text{H}_2\text{O})_6]^{3+}[Fe(H2O)6]3+
[Cu(H2O)6]2+[\text{Cu}(\text{H}_2\text{O})_6]^{2+}[Cu(H2O)6]2+
41 exam-style questions on OCR GCSE Chemistry Identifying the products of chemical reactions. Each one has a worked solution and a mark scheme showing where the marks go.