Write the observations and balanced equations for the following r… - Vidyadip

Question

Write the observations and balanced equations for the following reactions :
(i) Sodium hydroxide is added drop by drop, till in excess, in a solution of zinc sulphate.
(ii) Ammonium hydroxide is added first in small quantity and then in excess to a solution of copper sulphate.
(iii) Excess of ammonium hydroxide is added to a substance obtained by the action of hydrochloric acid in silver nitrate.

✓

Answer

(i) Observations : First a white gelatin like precipitate of zinc hydroxide is formed, which dissolves in excess of sodium hydroxide to form a clear solution of sodium zincate.

(ii) Observations :
(1) With small amount of ammonium hydroxide, it forms a bluish white precipitate.
(2) With excess of ammonium hydroxide, the precipitate dissolves to form deep blue coloration.

(iii) Observations :
(1) When hydrochloric acid is added to silver nitrate solution it forms a curdy white precipitate of silver chloride.
(2) The silver chloride (ppt.) dissolves in excess of ammonium hydroxide solution to form colourless solution.

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