The increasing order of pK_{a} for the follow | vedclass

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(A) The acidity of phenols is determined by the stability of the phenoxide ion formed after the loss of a proton.Electron-withdrawing groups ($-I$ and

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$(3), (4), (5), (2), (1)$

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(A) The acidity of phenols is determined by the stability of the phenoxide ion formed after the loss of a proton.Electron-withdrawing groups ($-I$ and $-M$ effects) stabilize the phenoxide ion and increase acidity,thereby decreasing $pK_{a}$.Electron-donating groups ($+I$ and $+M$ effects) destabilize the phenoxide ion and decrease acidity,thereby increasing $pK_{a}$.Comparing the substituents:$1$. $2, 4-$Dinitrophenol: Two strong $-M$ and $-I$ groups (most acidic).$2$. $4-$Nitrophenol: One strong $-M$ and $-I$ group.$5$. $3-$Chlorophenol: One $-I$ group (weakly acidic).$4$. Phenol: No substituent.$3$. $2, 4, 5-$Trimethylphenol: Three $+I$ groups (least acidic).Decreasing order of acidity: $(1) > (2) > (5) > (4) > (3)$.Since $pK_{a} = -\log(K_{a})$,the increasing order of $pK_{a}$ is the reverse of the acidity order: $(3) < (4) < (5) < (2) < (1)$.

The increasing order of $pK_{a}$ for the following phenols is:
$1$. $2, 4-$Dinitrophenol
$2$. $4-$Nitrophenol
$3$. $2, 4, 5-$Trimethylphenol
$4$. Phenol
$5$. $3-$Chlorophenol

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The increasing order of $pK_{a}$ for the following phenols is:$1$. $2, 4-$Dinitrophenol$2$. $4-$Nitrophenol$3$. $2, 4, 5-$Trimethylphenol$4$. Phenol$5$. $3-$Chlorophenol