Which of the following is singlet carbene?

1. (CH₃)₃C⁺

2. C₂H₅-CH

3. ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2^{-}$

4. CH₂ =CH-${\mathrm{CH}}_2^{+}$

Sulphur trioxide act as:

1. An electrophile             

2. A nucleophile

3. A homolytic agent         

4. A base

Allyl isocyanide has:

1. 9 σ, and 4π-bonds.

2. 8 σ, and 5π-bonds

3. 9 σ, and 3π-bonds, 

4. 8 σ, and 3 π bonds

Buta-1,3-diene and But-2-yne are:

1. Position isomers

2. Functional isomers

3. Chain isomers

4. Tautomers

Diastereomers can be separated by:

1. Fractional distillation

2. simple distillation

3. electrophoresis

4. all of these

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 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