Question

The following table shows the test 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 minimum quantity first and then in excess	A dirty white precipitate is formed which dissolves in excess to form a clear solution	(1)
To solution Y ammonium hydroxide is added in the minimum quantity first and then in excess	A pale blue precipitate is formed which dissolves in excess to form a clear inky blue solution.	(2)
To solution W a small quantity of sodium hydroxide solution is added and then in excess.	A white precipitate is formed which remains insoluble.	(3)
To a salt Z calcium hydroxide the solution is added and then heated.	A pungent smelling gas turning moist red litmus paper blue is obtained.	(4)

 

Answer 1

1)Zn²⁺

2) Cu²⁺

3) Ca²⁺

4) `NH_4^(+)`