The following table shows the tests a student performed on four different aqueous solution 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 excesss. 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)

ICSE Class 10 Chemistry 2015 Solved Paper

Question : 56

Total: 85

The following table shows the tests a student performed on four different aqueous solution 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 excesss.	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 Wa 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)

Solution:

(i) X=Zn++=Zinc ion.
(ii) Y=Cu++=Copper ion.
(iii) Z=Ca++=Calcium ion.
(iv) W=NH4+=Ammonium ion.

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