See image — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Step 1 - Concept: In SN1 reactions, the rate-determining step is the formation of a carbocation intermediate. The overall rate depends on (i) the stability/ease of formation of the carbocation, which is influenced by the leaving group ability, (ii) the ionizing power (polarity/nucleophilicity) of the solvent, and (iii) the concentration of the substrate (since SN1 is first-order, only substrate concentration matters, not nucleophile concentration). Step 2 - Analyze option (a): Me3CCl vs Me3CBr in water. Bromide is a better leaving group than chloride (Br- is a weaker base, more stable anion). Therefore Me3CBr ionizes more readily than Me3CCl. The second reaction (Me3CBr) is more reactive in SN1. Option (a) is correct. Step 3 - Analyze option (b): Me3CCl + CH3OH (methanol solvent) vs Me3CCl + H2O (water solvent). Water is a more polar, more ionizing solvent than methanol. A more polar solvent stabilizes the developing charges in the transition state and the carbocation intermediate better, increasing the SN1 rate. Therefore the second reaction (in H2O) is more reactive. Option (b) is correct. Step 4 - Analyze option (c): Me3CCl + H2O at 1M concentration vs Me3CCl + H2O at 2M concentration. In SN1, the rate = k[substrate]. The rate depends on substrate concentration. At 2M concentration, the substrate concentration is higher, so the rate is faster. Therefore the second reaction (2M) is more reactive. Option (c) is correct. Step 5 - Since all three pairs (a), (b), and (c) correctly show the second reaction being more reactive than the first in SN1, the answer is (d) All of these. Therefore, the correct answer is D.