Question

A metal X forms a salt XSO₄. The salt XSO₄ forms a clear solution in water which reacts with sodium hydroxide solution to form a blue precipitate Y. Metal X is used in making electric wires and alloys like brass.

1. What do you think metal X could be?
2. Write the name, formula and colour of salt XSO₄.
3. What is the blue precipitate Y?
4. Write a chemical equation of the reaction which takes place when salt XSO₄ reacts with sodium hydroxide solution. Give the state symbols of all the reactants and products which occur in the above equation.

Answer 1

1. Metal X could be copper (Cu).
2. The salt XSO₄ is copper sulphate; its formula is CuSO₄, and it is blue in colour.
3. Copper hydroxide [Cu(OH)₂] is the blue precipitate.
4. \[\ce{CuSO4_{(aq)} + 2NaOH_{(aq)} -> Cu(OH)2_{(s)} + Na2SO4_{(aq)}}\]