Analytical Chemistry Question 195
Question: An aqueous solution of colourless metal sulphate M gives a white precipitate with $ NH_4OH $ . This was soluble in excess of $ NH_4OH $ . On passing $ H_2S $ through this solution a white ppt. is formed. The metal M in the salt is
Options:
A) Ca
B) Ba
C) Al
D) Zn
Show Answer
Answer:
Correct Answer: D
Solution:
[d] $ Z{n^{2+}}+2NH_4OH\xrightarrow{{}}\underset{Whiteppt.}{\mathop{Zn{{( OH )}_2}}}+2NH_4^{+} $
$ Zn{{( OH )}_2}+2NH_4OH\xrightarrow{{}} $
$ \underset{Soluble}{\mathop{{{( NH_4 )}_2}}}ZnO_2+2H_2O $
$ {{(NH_4)}_2}ZnO_2+H_2S\xrightarrow{{}}\underset{Whiteppt.}{\mathop{ZnS+}}2NH_4OH $
BETA
