GATE Environmental Chemistry: Fundamentals of Environmental Chemistry – Previous Year Questions

9 GATE previous year questions on Fundamentals of Environmental Chemistry (Environmental Chemistry, Environmental Science and Engineering) with answers and explanations, from every paper.

1. GATE 2021 ES Q13 (1 mark, Multiple choice) – Powdered-coal samples have(mass kg, carbon wt%):(2,88),(1,90),(2,80),(1,90). Find carbon weight percentage of the completely mixed sample.
2. GATE 2021 ES Q26 (1 mark, Multiple choice) – Find nitrogen oxidation states in NH₄⁺,NO₂⁻ and NO, respectively.
3. GATE 2022 ES Q28 (1 mark, Multiple select) – For Gibbs free-energy change ΔG, select all correct statements.
4. GATE 2023 ES Q41 (2 marks, Multiple choice) – Match J Dalton, K Fick, L Henry, M Stokes with i Diffusion, ii Gas-mixture pressure, iii Gravitational settling, iv Gas–liquid phase transfer.
5. GATE 2024 ES Q13 (1 mark, Multiple choice) – The maximum coordination number of Sn4+ in the conventional complex-ion treatment used by this question is
6. GATE 2024 ES Q65 (2 marks, Numerical answer) – A bottle initially has 400 g ethanol. Half is used before a 90-day vacation. The bottle is left open and loses ethanol at .5 g/day. Find ethanol…
7. GATE 2025 ES Q14 (1 mark, Multiple choice) – Which reaction is a redox reaction?
8. GATE 2025 ES Q43 (2 marks, Multiple select) – Which statements about water solubility are correct?
9. GATE 2026 ES Q16 (1 mark, Multiple choice) – For the reversible elementary reaction A+B C+D,the forward and reverse rate constants are k f and k r. The equilibrium constant is