On strongly heating, a blue salt leaves a black residue. Which of the following cations can be prese — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Let's examine the colors of each of the compounds listed in the options. Step 2: NH4CNS is colorless, NaOH is a white solid/colorless solution, and K4[Fe(CN)6] is pale yellow but not typically described as a yellow precipitate in common tests. Step 3: Lead chromate (PbCrO4) is a well-known bright yellow precipitate widely used as a pigment (chrome yellow). Thus, option (b) is correct.