A student is given a beaker containing a mixture of insoluble barium sulfate (BaSO4\text{BaSO}_4BaSO4), dissolved sodium chloride (NaCl\text{NaCl}NaCl), and water. The student wants to obtain a pure, dry sample of solid BaSO4\text{BaSO}_4BaSO4 and a pure, dry sample of NaCl\text{NaCl}NaCl crystals.
Which of the following procedures describes the correct sequence of techniques to achieve this?
Filter the mixture. Wash the residue (BaSO4\text{BaSO}_4BaSO4) with distilled water and dry it. Heat the filtrate (NaCl\text{NaCl}NaCl solution) to evaporate some water, allow it to cool to crystallise, then filter and dry the NaCl\text{NaCl}NaCl crystals.
Filter the mixture. Wash the residue (NaCl\text{NaCl}NaCl) with distilled water and dry it. Heat the filtrate (BaSO4\text{BaSO}_4BaSO4 suspension) to evaporate some water, allow it to cool to crystallise, then filter and dry the BaSO4\text{BaSO}_4BaSO4 crystals.
Distill the mixture to collect the water and dissolved NaCl\text{NaCl}NaCl together in the distillate flask, leaving dry BaSO4\text{BaSO}_4BaSO4 behind as the residue in the distillation flask.
Evaporate the mixture to dryness to obtain a solid mixture. Add ethanol to dissolve the NaCl\text{NaCl}NaCl, filter to remove the insoluble BaSO4\text{BaSO}_4BaSO4, and evaporate the ethanol filtrate to obtain dry NaCl\text{NaCl}NaCl.
