Chemistry - Salt Analysis Question with Solution | TestHub

Question Explanation: The question provides characteristic reactions of an unknown cation X with chromate, carbonate, and ammonia, and asks which given statements about the cation are correct.

Concept: Qualitative Inorganic Analysis, Confirmatory Tests of Cations.

Solution:  

${\mathrm{Hg}}_2^{2+} +Cr{O}_4^{2-}\to H{g}_{2}Cr{O}_4\stackrel{N{H}_{4}OH}{\to }H{g}_{2}O+{\left(N{H}_4\right)}_{2}Cr{O}_4+H_{2}O$

(x)                                red or black red  Black

${\mathrm{Hg}}_2^{2+} +C{O}_3^{2-}\to H{g}_{2}C{O}_3\stackrel{∆}{\to }Hg+HgO+C{O}_2$

reddish brown or

light yellow

  HgO is red an well as yellow depending on particle size & method of preparation                    in cold - yellow                    

in hot - red.

Note: can it be Hg became Hg CrO₄ reacts with NH₄OH to give HgO which is yellow.