Question

The aqueous solution of which salt is coloured?

• A. $Zn({{NO}_3)}_2$
• B. $Li{NO}_3$
• C. $Co(NO{)}_3$
• D. Potash alum

Answer 1

The correct option is C $Co(NO{)}_3$

Cobalt(II) nitrate is a red-brown deliquescent salt that can be soluble in water and other polar solvents. $Co(NO{)}_3$ is formed when metallic cobalt or one of its oxides, hydroxides or carbonate reacts with nitric acid. We often prefer to use it in dyes and inks.