Question

A sample of furniture cleaner contains aqueous sodium chloride, aqueous ammonia, and sand. Plan an investigation to obtain a sample of pure water from the mixture.

A) Boil the mixture and collect the steam.
B) Filter the mixture to separate sand, then distill the remaining liquid.
C) Add more sodium chloride to the mixture and collect the precipitate.
D) Use a magnet to separate the sodium chloride, then filter the remaining liquid.

Answer 1

The correct method to obtain pure water from the mixture is to filter out the sand and then distill the remaining liquid to separate the water from aqueous sodium chloride and ammonia.

Step-by-step explanation:

To obtain a sample of pure water from the mixture containing aqueous sodium chloride, aqueous ammonia, and sand, the best method would be option B: Filter the mixture to separate the sand, then distill the remaining liquid. This process is a combination of filtration and distillation, where filtration removes the sand, which is insoluble in water, and distillation separates the aqueous sodium chloride and ammonia from the water based on differences in boiling points.

The distillation process involves heating the solution, which allows the water to evaporate and leaves behind the dissolved solids. The water vapor is then cooled and condenses back into pure water, which can be collected. This method ensures that the total mass of reactants equals the total mass of products, consistent with the law of conservation of mass.

It should be noted that adding more sodium chloride or using a magnet would not be effective in isolating pure water, as sodium chloride is soluble in water and neither component is magnetic.