Question

Which of the following statement are correct when a mixture of `NaCl` and `K_(2)Cr_(2)O_(7)` is gently warmed with conc.`H_(2)SO_(4)`?
A. Deep red vapours are evolved
B. The vapours when passed through NaOH solution, give yellow solution of `Na_(2)CrO_(4)`
C. Chlorine gas is evolved
D. Chromyl chloride is formed.

Answer 1

Correct Answer - A::B::D
(a,b,d) are correct.
(a) `4NaCl+K_(2)Cr_(2)O_(7)+6H_(2)SO_(4)rarrunderset("(Deep red)")underset()(2CrO_(2)Cl_(2))+4NaHSO_(4)+2KHSO_(4)+3H_(2)O`
(b) `CrO_(2)Cl_(2)+4NaOHrarrunderset("(Yellow)")(Na_(2)CrO_(4))+2NaCl+2H_(2)O`
(c) Chlorine gas is not evolved in the reaction. This is a wrong statement.
(d) `CrO_(2)Cl_(2)` is in the form of red coloured vapours (c) Chlorine is not coloured.