18.
The self indicating silica gel (impregnated with cobalt chloride) turns pink on absorbing moisture and becomes blue on heating. The pink and blue colour are respectively due to
A:
[Co(H2O)6]2+ and [CoCl4]2-
B:
[Co(H2O)6]2+ and Co2O3
C:
[Co(H2O)6]2+ and [Co(H2O)6]3+
D:
Co2+ and Co3+
The answer is:
A
