Barium sulfate is an insoluble salt. It may be prepared by mixing copper(II) sulfate solution with barium nitrate solution. $\text{CuSO}_4(aq) + \text{Ba(NO}_3)_2(aq) \rightarrow \text{Cu(NO}_3)_2(aq) + \text{BaSO}_4(s)$ What is the correct sequence of stages to obtain a pure, dry sample of barium sulfate from the reaction mixture?
- Astep 1: filter; step 2: evaporate the filtrate to dryness; step 3: leave the solid formed to cool
- Bstep 1: filter; step 2: evaporate the filtrate to the point of crystallisation; step 3: leave the filtrate to cool
- Cstep 1: filter; step 2: leave the residue in a warm place to dry; step 3: wash the residue with water
- Dstep 1: filter; step 2: wash the residue with water; step 3: leave the residue in a warm place to dry