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
Observations
Conclusions
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. (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)

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Solution

(i) Here solution X, must be zinc as, when ammonium hydroxide is added with zinc sulfate then, a dirty white precipitate of zinc (II) hydroxide is formed which form a clear solution in excess ammonium hydroxide. So, the cation present is Zn²⁺.
(ii) Here solution Y, must be copper as, when ammonium hydroxide is added with copper sulfate salt then, a pale blue precipitate of copper (II) hydroxide is formed which dissolves to form a clear inky blue solution in excess ammonium hydroxide. So, the cation present is Cu²⁺.
(iii) Here solution W, must be magnesium as, when sodium hydroxide is added with magnesium sulfate salt then, a white precipitate of magnesium hydroxide is formed which remains insoluble even after adding excess sodium hydroxide. So, the cation present is Mg²⁺.
(iv) Here salt Z, must be ammonium salt as when ammonium salt is added to calcium hydroxide and heated then a displacement reaction takes place in which calcium replaces ammonia to form calcium salt and ammonium hydroxide is formed which is a pungent-smelling gas that turns moist red litmus paper to blue due to its basic nature. So, the cation present in salt Z, is (NH₄)⁺.

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${Ca}^{2 +}$ The following table shows the test students performed on four different aqueous solutions which are X, Y, Z and W. Based on the observation provided, identify the cations present.

Chemical test	Observation	Conclusion
To solution X, ammonium hydroxide is added in minimum quantity first and then 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 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 ammonium hydroxide is added first and then in excess.	A white precipitate is formed which remain 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)

Q. The following table shows the test a student performed on four different aqueous solution which are X, Y, Z and W. Based on the observations provided, identify the action 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.
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.
To solution W a small quantity of sodium hydroxide solution hydroxide solution is added and then in excess.	A white precipitate is formed which remains insoluble.
To a salt Z calcium hydroxide solution is added and then heated.	A pungent smelling gas turning moist red litmus paper blue is obtained.

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Chemical Test	Observations	Conclusions
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.	(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)