Question

When a mixture of $NaCl$ and $K_{2}Cr_{2}O_{7}$ is gently warmed with concentrated $H_{2}SO_{4}$ :
(i) An orange-red vapour is evolved.
(ii) The vapour formed, when passed into $NaOH$ solution, gives yellow solution of $Na_{2}CrO_{4}$ .
(iii) Chlorine gas is not evolved at all.
(iv) Chromyl chloride gas is formed.
(v) $SnCl_{4}$ used instead of $NaCl$ also gives the same observations.

• A. All statements are correct
• B. (i), (iii) and (v) statements are correct
• C. (i), (ii) and (iv) statements are correct
• D. None of the statements are correct

Answer 1

Answer: (C)

Statements (i), (ii) and (iv) are correct.
$CrO_{2}Cl_{2}$ gas is liberated (orange red coloured). Its reaction with $NaOH$ gives yellow solution of $Na_{2}CrO_{4}$ , partially covalent halides like $SnCl_{4}$ do not give this test.