Question

Some of alkali metal salts are coloured $N{a}_{2}Cr{O}_4-$ yellow, $KMn{O}_4-$ pink, $K_{2}Mn{O}_4$ -green. It is due to:

• A. cations are coloured ions
• B. anions are coloured ions
• C. both $A$ and $B$
• D. none of the above

Answer 1

The correct option is B anions are coloured ions

Alkali salts are colourless

$NaCl$ colourless $N{a}_{2}Cr{O}_4$ - yellow since $Cr{O}_4^{3-}$ is yellow

$KCl$ colourless $K_{2}Cr{O}_4$ - yellow $KMn{O}_4$ - pink since $Mn{O}_4^{-}$ is pink $K_{2}Mn{O}_4$ - green since $Mn{O}_4^{2-}$ is green

anion are colourful due to presence of unpaired electron.