A white sublimable solid, when boiled with an NaOH solution, gives a colourless gas that turns Nessler's reagent brown. The solid, on being heated with solid K2Cr2O7 and concentrated H2SO4, gives red

Question

A white sublimable solid, when boiled with an NaOH solution, gives a colourless gas that turns Nessler's reagent brown. The solid, on being heated with solid K2Cr2O7 and concentrated H2SO4, gives red brown vapours. The white solid can be:

Prashant Kotian · Accepted Answer

Correct answer: B,C. Step 1: Adding NH4Cl and NH4OH to CrCl3 precipitates chromium(III) as a green gelatinous hydroxide, Cr(OH)3 (compound A). Step 2: Reacting Cr(OH)3 with sodium peroxide (Na2O2) in water oxidizes the Cr(III) to Cr(VI), forming a yellow solution of sodium chromate, Na2CrO4 (compound B). Step 3: When lead acetate is added to the sodium chromate solution, it forms a bright yellow precipitate of lead chromate, PbCrO4 (compound C). Thus, option (d) is the correct answer.

💡 Solution & Explanation

Practice 22,000+ questions like this