Chemistry MDCAT MCQs

Organic, inorganic & physical chemistry MCQs

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Showing 305 MCQs in Chemistry
Chemistry
A. Retention of configuration
B. Inversion of configuration giving (S)-2-butanol
C. Racemization
D. No reaction
Answer: SN2 proceeds with Walden inversion: the nucleophile attacks from the back side of the C-Br bond, inverting the stereochemistry from (R) to (S).
Chemistry
A. CH3COOH > ClCH2COOH > Cl2CHCOOH > Cl3CCOOH
B. Cl3CCOOH > Cl2CHCOOH > ClCH2COOH > CH3COOH
C. All have the same acidity
D. ClCH2COOH > Cl3CCOOH > Cl2CHCOOH > CH3COOH
Answer: Chlorine is electron-withdrawing (inductive effect). More Cl atoms increase acidity by stabilizing the conjugate base (carboxylate anion) through electron withdrawal.
Chemistry
A. Ethyl phosphate
B. Chloroethane (ethyl chloride)
C. Ethyl dichlorophosphate
D. Phosphoric acid
Answer: PCl5 converts alcohols to alkyl chlorides: C2H5OH + PCl5 -> C2H5Cl + POCl3 + HCl. The OH group is replaced by Cl.
Chemistry
A. 2n
B. 2^n
C. n!
D. n^2
Answer: Maximum stereoisomers = 2^n where n is the number of chiral centers. However, meso compounds may reduce this number if the molecule has internal symmetry.
Chemistry
A. Propylbenzoic acid
B. Benzoic acid
C. Phenol
D. No reaction
Answer: Hot KMnO4 oxidizes any alkyl group on benzene (with at least one benzylic H) to -COOH, producing benzoic acid regardless of the alkyl chain length.
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