Some Chemical Reactions MCQs with Answers

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In an endothermic reaction, the total energy of the products is greater than that of the reactants because energy is absorbed from the surroundings.

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The rate of reaction is decreased, not increased, by an increase in activation energy.

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The cloudiness in the Lucas test appears due to the formation of alkyl chlorides, which are insoluble in the aqueous reaction medium.

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In oxidation reactions, electrons are lost by the substance being oxidized.

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Yeasts feed on sugar in the dough and produce carbon dioxide gas, which causes the dough to rise.

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Complete combustion of methane produces CO₂ + H₂O (carbon dioxide and water).

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The correct Arrhenius equation is K = Ae^(-Ea/RT), which relates the rate constant (K) to temperature and activation energy.

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The rate law is determined by the slow (rate-determining) step, so it is K₁[NO₂]².

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Sabatier-Senderens reaction is used to prepare alkanes by catalytic hydrogenation of unsaturated hydrocarbons.

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<strong>Acetyl chloride</strong> cannot be prepared directly from acetic acid because the reaction of acetic acid with thionyl chloride (SOCl₂) or PCl₅ produces acetyl chloride along with HCl gas, but the reaction is reversible and yields are poor due to the presence of the –OH group; acetyl chloride is instead typically prepared from acetic anhydride or sodium acetate.