Question

Give reasons:
(a) White Silver chloride turns grey in sunlight.
(b) Brown coloured copper powder on heating in air turns into black
coloured substance.
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Answer 1

Answer:

a) Silver chloride turns grey on exposure to sunlight because it decomposes in presence of sunlight to give silver (Ag). 2. Oxidation of copper powder gives black colour copper oxide.

b) When brown coloured copper powder is heated in air it reacts with atmospheric Oxygen and turns into black colour due to the formation of Copper Oxide which is actually black in colour. The black coloured copper oxide is actually Cupric Oxide (CuO) with an oxidation state of 2+ for copper metal.

Answer 2

Answer:

(a) Silver chloride turns grey on exposure to sunlight because it decomposes in presence of sunlight to give silver (Ag). 2. Oxidation of copper powder gives black colour copper oxide.

(b) The color of the heated copper powder becomes black when air is passed over it because of its reaction with oxygen i.e. air. When it reacts with oxygen it forms copper oxide which is black in color. if air is passed over copper, the metal will get oxidized again, forming black copper oxide.