Question

In the chromyl chloride test, the final step results in the formation of a yellow precipitate of the following:

Options

• PbCl₂

• PbCrO₄

• NaBr

• Pb(NO₃)₂

Answer 1

PbCrO₄ 

Explanation:

Chromyl chloride test:

\[\ce{K2Cr2O7 + 4Cl- + 3H2SO4 -> \underset{\underset{(Red vapours)}{Chromyl Chloride}}{2CrO2Cl2 (g) + K2}SO (aq) + 3H2O + 2SO^{2-}4}\]

\[\ce{CrO2Cl2 + 4NaOH -> \underset{\underset{(Yellow)}{Sodium Chromate}}{Na2CrO4 (aq) + 2}NaCl (aq) + 2H2O}\]

\[\ce{Na2CrO4 (aq) + (CH3COO)2pb (aq) -> \underset{\underset{(Yellow ppt.)}{lead chromate}}{PbCrO4 (s)} ↓ \underset{\underset{Acetate}{Sodium}}{2CH3COONa}}\]