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Self Assessment Test Answer Key

Q.65  Which one of the following follow the Markownikov’s rule?

A. 2-Methyl-2-butene
B. 2-Pentene
C. 2,3-Dimethyl-2-butene
D. 2-Butene

Solution: The correct answer is A.

Reason: This rule states that in the addition of an unsymmetrical reagent to an unsymmetrical alky, the negative part of the adding reagent goes to that carbon, constituting the double bond, which has least number of hydrogen atoms.

2,3-Dimethyl-2-butene, 2-Pentene, 2-Butene is a symmetrical alkene so they does not obey Markownikov’s rule but 2-Methyl-2-butene is unsymmetrical alkene and it obey Markownikow’s rule.

Q.30 Consider the following structural formula.

MCAT KEY

 

 

 

 

 

 

The correct name according to IUPAC is:

A) 5-Amino-4-methyl benzoic acid
B) 3-Methyl-2-Amino- benzoic acid
C) 2-Amino-4-methyl benzoic acid
D) 2-Amino-4-carboxy toluene

Solution: The answer is C) 2-Amino-4-methyl benzoic acid according to IUPAC.

Reason: If two or more substituents are different, then the substituent that is treated as a high priority group, is given the number 1 position in the benzene ring. Other groups are numbered counting from position 1 in the manner which gives them the lowest number.
The order of priority of the group (left to right)
–COOH, – NH2 , –R

• In the given structural formula higher priority group – COOH is given the number 1 in the benzene ring. Other groups such –NH2 are numbered by the counting from position 1.
• Other options (A, B and D) do not fulfil the basic rules of nomenclature.