The decreasing order of acidity of the follow | vedclass

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Question

(B) The acidity of terminal acetylenes depends on the stability of the conjugate base (carbanion) formed after the removal of the acidic proton. Elect

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$(i) > (ii) > (iv) > (iii)$

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(B) The acidity of terminal acetylenes depends on the stability of the conjugate base (carbanion) formed after the removal of the acidic proton. Electron-withdrawing groups $(EWG)$ stabilize the carbanion through $-R$ or $-I$ effects,thereby increasing acidity. Electron-donating groups $(EDG)$ destabilize the carbanion through $+R$ or $+I$ effects,thereby decreasing acidity. In the given compounds: $(i)$ has a $-CO_2Et$ group,which is a strong $EWG$ ($-R$ effect),making it the most acidic. $(ii)$ is phenylacetylene with no substituent. $(iv)$ has a $-CH_3$ group,which is an $EDG$ ($+I$ effect),making it less acidic than $(ii)$. $(iii)$ has a $-OCH_3$ group,which is a strong $EDG$ ($+R$ effect),making it the least acidic. Thus,the decreasing order of acidity is $(i) > (ii) > (iv) > (iii)$.

The decreasing order of acidity of the following terminal acetylenes is:

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