Question

An excess of potassium ions makes KCl crystals appear violet or lilac in colour since _________.

1 point

A. some of the anionic sites are occupied by an unpaired electron.

B. some of the anionic sites are occupied by a pair of electrons

C.there are vacancies at some anionic sites.

D. F-centres are created which impart colour to the crystals.

​

Answer 1

The correct option is D. F-centers are created which impart colour to the crystals.

Explanation:

• If we add excess potassium ions in a solution of KCL, then anions are created by some of the chlorine atoms which leave their place.

• The chlorine atoms make an attempt to form bonds with the excess potassium ions.

• As a result, electrons are released by the potassium ions.

• The released electrons deposit at the F center and impart more violet color to the mixture.