The stabilization of a carbocation by an attached methyl group is primarily due to:

A tertiary butyl carbocation is more stable than a secondary butyl carbocation because-

1. + R effect of ${CH}_3$ groups 

2. $-$R effect of $-$ CH₃  groups 

3. Hyperconjugation 

4. $-$l effect of $-$CH₃ groups 

The correct order with respect to –I effect of the substituents is:
(R = alkyl)

1. –NH₂ > –OR < –F
2. –NR₂ < –OR < –F
3. –NH₂ > –OR > –F
4. –NR₂ > –OR > –F

The most stable carbocation among the following is:

1.	`	2.
3.		4.

Hyperconjugation occurs among the following compounds:

What is the correct sequence of acidity for the following compounds?

Which amongst the following is the most stable carbocation:
 

1.		2.
3.		4.

Polarisation of electrons in acrolein may be written as:

1.  $\stackrel{+\delta }{C}{H}_2=CH-\stackrel{-\delta }{C}HO$

2.  $\stackrel{-\delta }{C}{H}_2=CH-\stackrel{+\delta }{C}HO$

3.  $\stackrel{-\delta }{C}{H}_2=CH-\stackrel{}{C}\stackrel{+\delta }{H}O$

4.  $\stackrel{+\delta }{C}{H}_2=CH-CH\stackrel{-\delta }{O}$