23. Which chemical process gives beer its brown color?
(A) Maillard reaction
(B) Caramelization
(C) Oxidation of ethanol
(D) Hydrolysis of starch
(E) All of above

19. The molecular formula of the ion is , where X is an element from Group 6A. What is the hybridization of X atom?(A) sp (B) sp2 (C) sp3 (D) dsp3 (E) d2sp3

20. Which ion has the largest ionic size among the following?(A) (B) (C) (D) (E)

21. Compare the following molecules, what is the order of decreasing bond order?1. 2. N2 3. (A) 1=2=3 (B) 3＞2＞1 (C) 1＞2＞3 (D) 2＞1=3 (E) 1=3＞2

22. Which of the following statements is correct?(A) BF₃ has 24 total valence electrons, is an exception to the octet rule, and has resonance.(B) BF₃ has 24 total valence electrons, is an exception to the octet rule, and does not haveresonance.(C) BF₃ has 24 total valence electrons, obeys the octet rule, and has resonance.(D) BF₃ has 22 total valence electrons, is an exception to the octet rule, and does not haveresonance.(E) BF₃ has 24 total valence electrons, obeys the octet rule, and does not have resonance.

24. Arrange the following bonds in order of decreasing polarity:1. H-H 2. C-F 3. Al-F 4. N-O(A) 1＞2＞3＞4 (B) 3＞2＞4＞1 (C) 1＞3＞2＞4(D) 1＞4＞2＞3 (E) 3＞4＞2＞1

25. The density of a gas is 2 g/L at 3 atm and 27oC. What is the molar mass of the gas (g/mol)?(A) 1.48 (B) 32 (C) 149.6 (D) 9.3 (E) 16.4

26. Which of the following reactions does not involve oxidation-reduction?(A) CH4 + 3O2→ 2H2O + CO2 (B) PCl3 + Cl2 →PCl5(C) 2Na + 2H2O →2NaOH + H2 (D) MnO2 + 4HCl→ Cl2 + 2H2O + MnCl2(E) CO2 + 2LiOH →Li2CO3 + H2O

27. Calculate the standard change in enthalpy for the reaction and select the correct answer: (A) exothermic reaction(B) endothermic reaction(C) no energy change for this reaction(D) Lack of makes calculation impossible.(E) None of the above.

28. Which of the following can be identified as a set of isotopes?Atomic nuclei containI. 20 protons and 20 neutrons. II. 20 protons and 22 neutrons.III. 21 protons and 19 neutrons. fV. 20 neutrons and 18 protons.V. 21 protons and 20 neutrons.(A) I, IV and II, V (B) I, II and III, fV (C) I, III and II, V(D) II, IV and III, V (E) I, II and III, V

29. Which of the following represents the electron configuration for an excited state of an oxygenatom?(A) 1s22s 22p4 (B) 1s 22s 22p5 (C) 1s22s22p33s1(D) 1s 22s 22p6 (E) 1s22s22p3