Question

what color are cu2+, ag+, co2+, ni2+, fe3+ after development and after ammonia in paper chromatography?

Answer 1

Paper chromatography of cations

The color developed by cations upon treatment with ammonia and developing agents are,

Cu2+ with ammonia gives a dark blue coloration for [Cu(NH3)4]2+

Ni2+ with ammonia and dimethylglyoxime gives a strawberry red coloration for [Ni(NH3)6]2+

Fe3+ forms a rusty brown coloration of hydroxide for Fe(OH)3

Co2+ forms a brownish-yellow coloration upon treatment with ammonia for [Co(NH3)6]2+

Ag+ with ammonia gives no color, such that is forms a colorless complex [Ag(NH3)2]+