4. What will be the major product of the following reaction?
(A)
(B)
(C)
(D) 
(E) None of the above 

40. 0.25S(0.25倍太陽質量)的恆星的壽命，大約有多少年？(A)25億年(B)50億年(C)100億年(D)200億年。

1. Consider the resonance of compound A, which one is not its resonance form? (A)(B)(C)(D)(E)

2. Which of the following compounds is not an aromatic compound? (A)(B)(C)(D)(E)

3. For each compound below, which one will give 3 signals in its normal, broadband decoupled 13C NMR spectra, (assume the resolution is good to identify all different signal) (A) Ⅰ, Ⅱ, Ⅲ (B) Ⅱ, Ⅲ (C) Ⅲ, IV, V (D) Ⅲ, V (E) None of the above

5. Which of the following reactions would not show primary kinetic isotope effect? (A)(B)(C)(D)(E) None of the above 

6. When bromide AK is treated with NaOEt， four2- butene are possible products. (A) AK-a and AK-b are obtained (B) AK-a and AK-d are obtained(C) AK-b and AK-c are obtained (D) None of the above

7. Solvent is an important factor in the nucleophilic reaction. We classified solvent into several categories. What is the best description of acetone? Acetone is: (A) nonpolar aprotio (B) polar aprotic (C) polar protic (D) nonpolar protic (E) None of the above

8. Consider the spectrum illustrated below. Which of the following structures will be best for this spectrum? (A)(B)(C)(D)(E) None of the above

9. The average mass of a boron atom is 10.81. If you were able to isolate a single boron atom, what is the chance that you would randomly get an atom with mass 10.81?  (A) 0% (B) 0.81% (C) about 11% (D) 10.81% (E) greater than 50%.

10. Which of the statements below correctly describes the chair conformations of trans-1,4-dimethylcyclohexane? | (A) The two chair conformations are of equal energy. | (B) The higher energy chair conformation contains one axial methyl group and one equatorial methyl group. | (C) The lower energy chair conformation contains one axial methyl group and one equatorial methyl group. | (D) The higher energy chair conformation contains two axial methyl groups. | (E) The lower energy chair conformation contains two axial methyl groups. |