Question

If

Diagram

is mixed with $NaOH$ solution. Acid-base reaction occurs and proton is snatched from organic molecule. Which carbon will lose easily?

• A. $S$
• B. $P$
• C. $Q$
• D. $R$

Answer 1

The correct option is B $P$

$\text{Analyzing given Options}$

$\text{Option A:}$

When acid-base reaction occurs and $H^{+}$ is removed from carbon$-P,$ we get the following carbanion.

Diagram

Resonance of Conjugate Anion (For P) :

Carbon P will easily lose proton because the carbanion formed is stabilized due to resonance as negative charge will appear on both of the oxygen atom.

$\text{Option (b):}$

Diagram

Carbanions that will form on losing hydrogen from carbon Q is stabilized due to resonance as negative charge will appear on one oxygen atom only.

So, it will have less ability to lose proton as compared to P.

$\text{Option (c):}$

Diagram


Carbanion, that will form on losing hydrogen from carbon R is not resonance stabilized. So, it will have the least ability to lose proton.

$\text{Option (d):}$

Diagram

Carbanions that will form on losing hydrogen from carbon S is stabilized due to resonance as negative charge will appear on one oxygen atom only.

So, it will have less ability to lose proton as compared to P.
Therefore, the correct answer is option (A).