Question

The following table shows the tests a student performed on four different aqueous solutions which are X,Y,Z and W. Based on the observations provided, Identify the cation present

Chemical Test	Observation	Conclusion
To Solution X, ammonium hydroxide is added in minium quantity first and then in excess	A dirty white precipitate is formed which dissolves in excess to form a clear solution	(i)
To Solution Y, ammonium hydroxide is added in minimum quantity first and then in excess	A pale blue precipitate is formed which dissolves in excess to form a clear inky blue solution	(ii)
To solution W, A small quantity of sodium hydroxide solution is added and then in excess	A white precipitate is formed which remains insoluble	(iii)
To a salt Z, calcium hydroxide solution is added and then heated	A pungent smelling gas turning moist red litmus paper blue is obtained	(iv)

Answer 1

(i) Zn²⁺
(ii) Cu²⁺
(iii) Ca²⁺
(iv) NH₄⁺