25. Which one of the following molecular formulae can represent a pair of mirror image isomers?
(A) H₂NCH₂COOH
(B) H₂NCH(CH₃)COOH
(C) H₂NCH₂CH₂COOH
(D) H₂NCH₂COOCH₃
(E) (CH₃)₂CHCOOH

21. Which one of the following descriptions for the Beer’s law is incorrect? (A) Beer’s law is ordinarily represented as A =εbs. (B) For a mixture, the total absorbance at a λ=the sum of individual absorbance if there is no intermolecular interaction. (C) Beer’s law is more suitable for concentrated solutions. (D) Negative deviations are always observed if polychromic radiations are used. (E) The b term in the equation of item (a) means the optical length.

22. Buffer solutions are very important for many analytical applications. Which one of the following descriptions about buffer solutions is incorrect? (A) Buffer solutions are generally from conjugate acid/base pairs. (B) Buffer solutions can resist to changes of pH when the solutions are diluted or added with strong acids or bases. (C) The buffer capacity is the measurement of ability that resists to pH changes. (D) The buffer capacity of a solution is determined by the strength of the conjugate acid/base pair. (E) The pH of a buffer solution can be determined by pH=pKa + log ([base]/[acid]).

23. Which one of the following apparatuses is not used for measurement of volume? (A) Volumetric (B) Pipet (C) Buret (D) Test tube (E) All of these are used for measurement of volume.

24. What is the major product of the following reaction?(A) (B)(C) (D) (E) None of the above

26. A chain reaction is one that : (A) involves a series of steps (B) involves two steps with similar energies of activation (C) is initiated by heat (D) requires the addition of an external terminating agent (E) involves a reaction in which the propagation steps also produce the product and initiator necessary for another propagation cycle

27. Which statement best describes 1,3-butadiene? (A) 1,3-butadiene is less stable than 1,4-pentadiene due to steric crowding. (B) 1,3-butadiene is more stable than 1,4-pentadiene because of less steric crowding. (C) 1,3-butadiene is less stable than two molecules of 1-butene. (D) 1,3-butadiene is more stable than 1,4-pentadiene due to resonance energy. (E) 1,3-butadiene’s carbon atoms are sp3 hybridized.

28. Which is the general formula for cyclic hydrocarbons with one double covalent bond between adjacent atoms? (A) CnH2n+2 (B) CnH2n (C) CnH2n-2 (D) CnH2n-4 (E) CnH2n-6

29. What is the major product of the following reaction? (A) (S) 2-butanol (B) (R)2-butanol (C) racemic mixture of 2-butanol (D) e.e of (S)-butanol (E) diastereomeric mixture of 2-butanol

30. How many absorptions will the following compound have in its carbon NMR spectrum? (A) 3 (B) 4 (C) 5 (D) 6 (E) 7

31. The pinacol rearrangement proceeds via              intermediate. (A) carbanion (B) carbocation (C) radical (D) lone pair (E) neutral