Question

Which of the following group(s) show $+M$ effect?

• A. $-\stackrel{-}{C}{H}_2$
• B. $-NHCOR$
• C. $-O^{-}$
• D. $-OH$

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A $-\stackrel{-}{C}{H}_2$
B $-NHCOR$
C $-O^{-}$
D $-OH$

$+M$ effect :
Here transfer of $\pi$ (pi) electron takes place from the atom/group towards the conjugated system.
If a conjugated system has electron donating group attached, then it shows $+M$ effect.

$+M$ series :
$-\stackrel{-}{C}{H}_2>-\stackrel{-}{N}H-O^{-}>-N{H}_2>-NHR>-N{R}_2>-OH>-OR>-NHCOR>-OCOR>-Ph>-F>-Cl>-Br>-I>-NO$