QJEEM23Chd729: JEE Main 2023 Chemistry - Class 12 JEEM23Chd729 Solution: K 2 Cr 2 O 7 paper acidified with dilute H 2 SO 4 turns green…

Question

Verified Solution • 2025–26 Session moderate

$K_{2} {Cr}_{2} O_{7}$ paper acidified with dilute $H_{2} {SO}_{4}$ turns green when exposed to :

Accepted Answer

\mathrm{SO}_{2}

gets oxidised in presence of

\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}

and it converts to

\mathrm{Cr}^{+3}

in presence of dil.

\mathrm{H}_{2} \mathrm{SO}_{4}

.

Similarly,

\mathrm{H}_{2} \mathrm{~S}

can also get oxidized to sulphur.

However, most appropriate is (A) Sulphur dioxide.

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