Chemistry 0620 · IGCSE · Ions and ionic bonds

Ions and ionic bonds — practice question

The equations showing the reaction of water with anhydrous cobalt(II) chloride and anhydrous copper(II) sulfate are given below. $\text{CoCl}_2(s) + 6\text{H}_2\text{O}(l) \rightarrow \text{CoCl}_2\cdot6\text{H}_2\text{O}(s)$ $\text{CuSO}_4(s) + 5\text{H}_2\text{O}(l) \rightarrow \text{CuSO}_4\cdot5\text{H}_2\text{O}(s)$ Which statement is incorrect?

  • ABoth reactions can be reversed by changing the conditions.
  • BBoth reactions can be used as a test for water.
  • CThe colour change observed when hydrated copper(II) sulfate is heated is from blue to white.
  • DThe colour change observed when water is added to anhydrous cobalt(II) chloride is from pink to blue.

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