Transition and InnerTransition Elements - Result Question 147
####47. Which of the following statement(s) is/are correct when a mixture of $NaCl$ and $K _2 Cr _2 O _7$ is gently warmed with conc. $H _2 SO _4$ ?
$(1998,2 M)$ (b) Vapours when passed into $NaOH$ solution gives a yellow solution of $Na _2 CrO _4$
(c) Chlorine gas is evolved
(d) Chromyl chloride is formed
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Answer:
Correct Answer: 47. $(a, b, d)$
Solution:
- $4 NaCl+K _2 Cr _2 O _7+6 H _2 SO _4 \longrightarrow \underset{\text { Chromyl chloride }}{2 CrO _2 Cl _2}$ Chromyl chloride (red vapour)
$+4 NaHSO _4+2 KHSO _4+3 H _2 O$
$CrO _2 Cl _2+4 NaOH \longrightarrow Na _2 CrO _4+2 NaCl+2 H _2 O$ yellow solution