76. Which of the following molecules is chiral? 

72. The syntheses shown here are unlikely to occur as written. What is wrong with each? 

73. Which of the reactions below would not produce n-butylamine ?

74. Determine the product of the synthetic sequence below. 

75. A chiral C7H16O2 diol is oxidized by PCC in CH2Cl2 to an achiral C7H12O2 compound. Which of the following would satisfy these facts?

77. Stereoisomers I and II undergo E2 elimination on treatment with sodium ethoxide in ethanol. One isomer reacts 500 times faster than the other. Also, one isomer gives X as the only product, whereas the other gives Y together with some X. Which of the following statements provides the best assignment of I and II?  (A) II reacts faster and gives both Y and X (B) II reacts faster and gives only X (C) I reacts faster and gives both Y and X (D) I reacts faster and gives only Y (E) I reacts faster and gives only X

78. What product is wrong when carvone is treated with the following reagents? 

79. What is the expected product from the reaction sequence drawn below?  

80. Only one of the following amines will lose its nitrogen atom as trimethyl amine by repeated Hofmann elimination reactions (exhaustive methylation followed by heating with AgOH). Identify that amine.

1 下列何種情況屬於累退稅？ (A)平均稅率隨所得增加而增加 (B)邊際稅率隨所得增加而增加 (C)邊際稅率隨所得增加而不變 (D)平均稅率隨所得增加而遞減

2 其他情況不變，下列有關免稅額與扣除額對有效稅率（effective tax rate）的影響之敘述，何者錯誤？ (A)免稅額增加將使得有效稅率下降 (B)扣除額增加將使得有效稅率下降 (C)免稅額占稅基的比重愈高，則有效稅率愈低 (D)扣除額占稅基的比重愈低，則有效稅率愈低