Question

Give one test to distinguish between the following pairs of chemicals:
Sodium sulfate solution and sodium chloride solution.

Answer 1

Sodium chloride and sodium sulfate, both of them are the salts of the element sodium that belongs to the s-block. Both the solutions can be separated by barium chloride, one of them forms white precipitate while the other does not react with it.

Complete step by step solution:
Sodium chloride is a salt of the element sodium that belongs to the group 1 of the s-block and it has a formula $NaCl$. Sodium chloride solution means when this salt is dissolved in water.
Sodium sulfate is also a salt of the element sodium that belongs to the group 1 of the s-block and it has a formula $N{{a}_{2}}S{{O}_{4}}$. Sodium sulfate solution means when this salt is dissolved in water.
Both solutions can be distinguished with the help of barium chloride.
Barium chloride is also a salt, so when salt has different cations or anions, substitution will take place.
So when the sodium sulfate solution reacts with barium chloride, it forms a white precipitate of barium sulfate and this precipitate is insoluble in mineral acids. The reaction is given below:
$BaC{{l}_{2}}+N{{a}_{2}}S{{O}_{4}}\to BaS{{O}_{4}}+2NaCl$
But when the sodium chloride is reacted with barium chloride no reaction takes place because both of them have the same anion i.e., chloride.

Note: There is another method of distinguishing them: by treating both the compounds with silver nitrate solution. This time the sodium chloride will form a white precipitate but the sodium sulfate will show no reaction.