Two metals X and Y form the salts XSO<sub>4</sub> and Y<sub>2</sub>SO<sub>4</sub>, respectively. The solution of salt XSO4 is blue in colour whereas that of Y<sub>2</sub>SO<sub>4</sub> is colourless. When barium chloride solution is added to XSO<sub>4</sub> solution, then a white precipitate Z is formed along with a salt which turns the solution green. And when barium chloride solution is added to Y<sub>2</sub>SO<sub>4</sub> solution, then the same white precipitate Z is formed along with colourless common salt solution.<br><b>(a)</b> What could the metals X and Y be?<br><b>(b)</b> Write the name and formula of salt XSO<sub>4</sub>.<br><b>(c)</b> Write the name and formula of salt Y<sub>2</sub>SO<sub>4</sub>.<br><b>(d)</b> What is the name and formula of white precipitate Z?<br><b>(e)</b> Write the name and formula of the salt which turns the solution green in the first case.