Question

Which of the following statement is correct when a mixture of $NaCl$ and $K_{2}C{r}_2{O}_7$ is gently warmed with $conc.H_{2}S{O}_4$ ?
$1$ . A deep red vapour is evolved
$2.$ The vapour when passed into $NaOH$ solution gives a yellow solution of $N{a}_{2}Cr{O}_4$
$3.$ Chlorine gas is evolved
$4.$ Chromyl chloride is formed

• A. 1, 2, 4
• B. 1, 2 ,3
• C. 2, 3, 4
• D. all are correct

Answer 1

Answer: (A)

$4NaCl+K_2{\left(Cr\right)}_2{O}_7+6H_2{\left(SO\right)}_4\left(conc.\right)\to 2{\left(KHSO\right)}_4+4{\left(NaHSO\right)}_4+\underset{\underset{Chromylchloride}{\left(orangered\right)}}{2{\left(CrO\right)}_2{\left(Cl\right)}_2}+3H_{2}O$
Chromyl chloride vapours when passed through $NaOH$ solution gives a yellow solution of $N{a}_{2}Cr{O}_4$ .
$Cr{O}_{2}C{l}_2+4NaOH\to N{a}_{2}Cr{O}_4+2NaCl+2H_{2}O$