Question

Which of the following statement(s) is/are correct when a mixture of $NaCl$ and $K_{2}C{r}_2{O}_7$ are gently warmed with conc. $H_{2}S{O}_4$ ?

• A. A deep red vapour is evolved
• B. The vapour when passed into $NaOH$ solution gives a yellow solution of $N{a}_{2}Cr{O}_4$
• C. Chlorine gas is evolved
• D. Chromyl chloride is formed

Answer 1

Answer: (A), (B), (C), (D)

Chromyl chloride is formed

When a mixture of $NaCl$ is heated with $K_{2}C{r}_2{O}_7$ in concentrated $H_{2}S{O}_4$, red vapour of chromyl chloride $\left(Cr{O}_{2}C{l}_2\right)$ is produced. Vapours of chromyl chloride when passed through $NaOH$ solution turns yellow due to the formation of $N{a}_{2}Cr{O}_4$. Some chlorine gas is also evolved owing to the following side reaction:
$6C{l}^{-}+C{r}_2{O}_7^{2-}+14H^{+}\to 3C{l}_2\left(g\right)\uparrow +2C{r}^{3+}+7H_{2}O$