NaCl reacts with conc. $\mathrm{H}_{2} \mathrm{SO}_{4}$ and $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ to give reddish fumes (B), which react with NaOH to give yellow solution (C). (B) and (C) respectively are ;

(A) $\mathrm{CrO}_{2} \mathrm{Cl}_{2}, \mathrm{Na}_{2} \mathrm{CrO}_{4}$

(B) $\mathrm{Na}_{2} \mathrm{CrO}_{4}, \mathrm{CrO}_{2} \mathrm{Cl}_{2}$

(C) $\mathrm{CrO}_{2} \mathrm{Cl}_{2}, \mathrm{KHSO}_{4}$

(D) $\mathrm{CrO}_{2} \mathrm{Cl}_{2}, \mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$

JEE Main · 2024 · 27 Jan 2024 · Shift 1 · d and f Block Elements

NaCl reacts with conc.

H_{2} SO_{4}

and

K_{2} Cr_{2} O_{7}

to give reddish fumes (B), which react with NaOH to give yellow solution (C). (B) and (C) respectively are ;

Answer: (A)

NaCl reacts with concentrated

H_{2} S O_{4}

and

K_{2} C r_{2} O_{7}

to release reddish-brown fumes of chromyl chloride:

4 NaCl + K_{2} C r_{2} O_{7} + 6 H_{2} S O_{4} \to 2 Cr O_{2} C l_{2} (B) + \dots

Chromyl chloride then hydrolyzes in NaOH to a yellow solution of sodium chromate:

Cr O_{2} C l_{2} + 4 NaOH \to N a_{2} Cr O_{4} (C) + 2 NaCl + 2 H_{2} O

(B) = Cr O_{2} C l_{2}

(C) = N a_{2} Cr O_{4}

JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Single correct option