+R Effect

Why does the ${\mathrm{NO}}_2$ group show its effect only in ortho?

Anisole on reaction with HI produces only phenol and methyl iodide. Give reason?

1. 6
2. 5
3. 3
4. 4

1. 5
2. 6
3. 3
4. 4

1. i > ii > iii > iv
2. iii > i > ii > iv
3. ii > iii > i > iv
4. iii > ii > i > iv

Actinoid contraction is greater from element to element than lanthanoid contraction. Why?

1. 
2. 
3. 
4. No product is formed

Explain the resonance structure of benzoic acid.

1. $\left(III\right)$
2. $\left(IV\right)$
3. $\left(II\right)$
4. $\left(I\right)$

Compare the structures of H₂O and H₂O₂.

1. $I>II>IV>III$
2. $II>I>III>IV$
3. $I>II>III>IV$
4. $IV>III>II>I$

Is $-{\mathrm{OCH}}_3$ an activator or deactivator?

The most stable enolic form of 2, 4-pentanedione

1. $-\stackrel{-}{C}{H}_2$
2. $-NHCOR$
3. $-O^{-}$
4. $-OH$

1. Here transfer of $\pi$ (pi) electron takes place from the atom/group towards the conjugated system.
2. Phenoxide ion does not show $+R$ effect because it has lone pair of electrons.
3. If a conjugated system has electron withdrawing group attached, then it shows $+R$ effect.
4. All of the above.

1. a
2. b
3. c
4. d

1. $-CHO$
2. $-N{O}_2$
3. $-N{H}_2$
4. $-COC{H}_3$

1. 5
2. 6
3. 4
4. 3

1. $+M$ or $+R$
2. $-M$ or $-R$
3. $+I$
4. Both (a) and (c)

The basicity of aniline is less than cyclohexylamine. This is due to:

1. -R effect of amine group

2. -I effect of amine group

3. +R effect of amine group

4. Hyperconjugation effect

1. $-N{H}_2$
2. $-OR$
3. $-COR$
4. $-COOH$

1. $+M$ or $+R$
2. $-M$ or $-R$
3. $+I$
4. Both (a) and (c)

1. True
2. False

1. $\stackrel{+}{C}{H}_3$
2. $C{H}_3\stackrel{+}{C}HC{H}_3$
3. $C{H}_3\stackrel{+}{C}{H}_2$
4. $C{H}_3-\stackrel{+}{\underset{\underset{C{H}_3}{|}}{C}}-C{H}_3$

1. A is more stable than B
2. A and B have the same stability
3. B is more stable than A
4. No comparision of stability can be made

Explain why alkyl groups act as electron donors when attached to a π system.

1. 6
2. 5
3. 3
4. 4

1. Here transfer of $\pi$ (pi) electron takes place from the atom/group towards the conjugated system.
2. Phenoxide ion does not show $+R$ effect because it has lone pair of electrons.
3. If a conjugated system has electron withdrawing group attached, then it shows $+R$ effect.
4. All of the above.