A student is given a beaker containing a mixture of insoluble barium sulfate ( $BaSO4\text{BaSO}_4$ ), dissolved sodium chloride ( $NaCl\text{NaCl}$ ), and water. The student wants to obtain a pure, dry sample of solid $BaSO4\text{BaSO}_4$ and a pure, dry sample of $NaCl\text{NaCl}$ crystals.

Which of the following procedures describes the correct sequence of techniques to achieve this?

Filter the mixture. Wash the residue ( $BaSO4\text{BaSO}_4$ ) with distilled water and dry it. Heat the filtrate ( $NaCl\text{NaCl}$ solution) to evaporate some water, allow it to cool to crystallise, then filter and dry the $NaCl\text{NaCl}$ crystals.

Filter the mixture. Wash the residue ( $NaCl\text{NaCl}$ ) with distilled water and dry it. Heat the filtrate ( $BaSO4\text{BaSO}_4$ suspension) to evaporate some water, allow it to cool to crystallise, then filter and dry the $BaSO4\text{BaSO}_4$ crystals.

Distill the mixture to collect the water and dissolved $NaCl\text{NaCl}$ together in the distillate flask, leaving dry $BaSO4\text{BaSO}_4$ behind as the residue in the distillation flask.

Evaporate the mixture to dryness to obtain a solid mixture. Add ethanol to dissolve the $NaCl\text{NaCl}$ , filter to remove the insoluble $BaSO4\text{BaSO}_4$ , and evaporate the ethanol filtrate to obtain dry $NaCl\text{NaCl}$ .

Which of the following procedures describes the correct sequence of techniques to achieve this?

Distill the mixture to collect the water and dissolved $NaCl\text{NaCl}$ together in the distillate flask, leaving dry $BaSO4\text{BaSO}_4$ behind as the residue in the distillation flask.

Elements, compounds and mixtures

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Elements, compounds and mixtures Questions