Match the transformations in column I with appropriate options in column II
| Column I | Column II |
|---|---|
| (A) | (p) phase transition |
| (B) | (q) allotropic change |
| (C) | (r) is positive |
| (D) | (s) is positive |
| (t) is negative |
Answer: A → I, A → III, A → IV, B → III, B → IV, C → V, D → I, D → II, D → V
Solution
(A) Sublimation of CO₂: Solid to gas is a phase transition (p), requires heat input so ΔH > 0 (r), and increases disorder so ΔS > 0 (s). Matches: p, r, s
(B) Decomposition of CaCO₃: Endothermic reaction so ΔH > 0 (r), produces gas from solid increasing entropy so ΔS > 0 (s). Matches: r, s
(C) Formation of H₂ from atoms: Bond formation releases energy (exothermic), and two separate atoms combining into one molecule decreases entropy, so ΔS < 0 (t). Matches: t
(D) White phosphorus to red phosphorus: Allotropic change (q), also a phase transition in solid state (p), exothermic (more stable form) and decreases disorder so ΔS < 0 (t). Matches: p, q, t
(B) Decomposition of CaCO₃: Endothermic reaction so ΔH > 0 (r), produces gas from solid increasing entropy so ΔS > 0 (s). Matches: r, s
(C) Formation of H₂ from atoms: Bond formation releases energy (exothermic), and two separate atoms combining into one molecule decreases entropy, so ΔS < 0 (t). Matches: t
(D) White phosphorus to red phosphorus: Allotropic change (q), also a phase transition in solid state (p), exothermic (more stable form) and decreases disorder so ΔS < 0 (t). Matches: p, q, t
JEE Advanced · 2011 · 10 Apr 2011 · Paper 2 · Match the columns