Acidic K2Cr2O7 reacts with H2S to produce: — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Heavy metal nitrates of metals low in the electrochemical series (like silver and mercury) undergo thermal decomposition to yield the free metal rather than the metal oxide. Step 2: On heating, AgNO3 decomposes to Ag metal, NO2, and O2: 2AgNO3 -> 2Ag + 2NO2 + O2. Similarly, Hg2(NO3)2 decomposes to yield liquid mercury (Hg), NO2, and O2. Step 3: Because both mercury(I) nitrate and silver nitrate decompose to give the metallic elements, both options (a) and (d) are correct (as reflected by the 'a, d' answer key).