Question

The increasing order of $p{K}_a$ value of the following is:
(i) $CH\equiv CH$
(ii) and (iii) ref. image

• A. $III>I>II$
• B. $II>I>III$
• C. $I>III>II$
• D. $I>II>III$

Answer 1

The correct option is A $III>I>II$

More$P{K}_a$ value means less$K_a$ and compound would be less acidic,

in (i) the negative charge is stable by E.N. of double bond, and in 3rd option negative charge is in the resonance.

So $III>I>II$ would be answer.