Sarthaks Test
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Assertion : Cuprous ion (Cu+) is colourless whereas cupric ion (Cu++) is blue in the aqueous solution. 

Reason : Cuprous ion (Cu+) has unpaired electrons while cupric ion (Cu++) does not.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

1 Answer

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Best answer

The correct option is (c) A is true but R is false.


Cuprous ions (Cu+) is colourless because it has no unpaired electrons in the 3d sub-shell as it has 3d10 configuration. The cupric ion (Cu++) has one unpaired electron as it has 3d9 configuration. By absorbing the visible light, the unpaired electron can migrate from one set of d-orbitals to another. Hence cupric ion (Cu++) in aqueous solution shows blue colour.

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