The pair of structures given below represent-
  

1.	Enantiomers	2.	Position isomers
3.	Conformers	4.	None of the above

In the following carbocations, the most stabile carbocation:

(1)  RCH₂C+H₃         

₍₂₎ 

₍₃₎                

 ₍₄₎ 

The number of optical isomers of pent-3-en-2-ol is:

1. 2             

2. 4

3. 8             

4. 16

The group named as benzal possesses .... nature.

(1) monovalent 

(2) bivalent

(3) trivalent

(4) tetravalent

Which of the following structures permits cis-trans isomerism?

1. X₂C=CY₂

2. XYC=CZ₂

3. X₂C=CXY

4. XYC=CXY

A compound contains 2 dissimilar asymmetric carbon atoms. The number of optically active isomers is

1. 2 

2. 3

3. 4

4. 5

The number of geometrical isomers in case of a compound with the structure,

CH₃-CH=CH-CH=CH-C₂H₅ are:

1. Four                 

2. Three

3. Two                 

4. Five

Geometrical isomerism is caused by-

1. Restricted rotation around C=C bond.

2. The presence of one asymmetric carbon atom.

3. The different groups attached to the same functional group.

4. None of the above.

Which of the following is optically active?

1. Alanine

2. 2-butanol

3. Lactic acid

4. All of these

The isomerism which exists between CH₃CHCl₂, and CH₂ClCH₂Cl is:

1. Chain            

2. Functional

3. Position isomerism      

4. Metamerism