Question

Read the above short write up and answer the following question :

Select the incorrect reaction_________.

• A. (C) In solid state + KBr + $conc.H_{2}S{O}_4\to$ Red gas
• B. (C) In solid state + KCl + $conc.H_{2}S{O}_4\to$ Red gas
• C. (C) In solid state + $FeC{l}_3+conc.H_{2}S{O}_4\to$ Red gas
• D. (C) In solid state + $HgC{l}_2+conc.H_{2}S{O}_4\to$ Red gas

Answer 1

The correct option is D (C) In solid state + $HgC{l}_2+conc.H_{2}S{O}_4\to$ Red gas

Compound C contains dichromate ion $\left(C{r}_2{O}_7^{2-}\right)$.

It reacts with KCl in presence of conc. sulfuric acid to form chromyl chloride $\left(Cr{O}_{2}C{l}_2\right)$ which is the red gas E.

$4KCl+K_{2}C{r}_2{O}_7+6H_{2}S{O}_4\to 2Cr{O}_{2}C{l}_2\uparrow +6KHS{O}_4+3H_{2}O$

$HgC{l}_2$ does not give chromyl chloride test.

Therefore, the correct option is D.