The pK_{a} values of X, Y, Z respectively are | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

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

Vedclass · Accepted Answer

Vedclass · Answer

(A) The acidity of phenols is determined by the stability of the phenoxide ion formed after the loss of a proton. Electron-withdrawing groups (like $-NO_2$) increase acidity (lower $pK_{a}$),while electron-donating groups (like $-CH_3$) decrease acidity (higher $pK_{a}$).$1$. $p$-Nitrophenol has a $-NO_2$ group at the para position,which exerts a strong $-R$ (resonance) and $-I$ (inductive) effect,making it the most acidic $(pK_{a} = 7.1)$.$2$. $m$-Nitrophenol has a $-NO_2$ group at the meta position,which exerts only a $-I$ effect,making it less acidic than $p$-nitrophenol $(pK_{a} = 8.3)$.$3$. $p$-Cresol has a $-CH_3$ group at the para position,which is an electron-donating group ($+I$ and hyperconjugation),making it the least acidic $(pK_{a} = 10.2)$.Thus,$X = m$-nitrophenol $(8.3)$,$Y = p$-nitrophenol $(7.1)$,and $Z = p$-cresol $(10.2)$.

The $pK_{a}$ values of $X, Y, Z$ respectively are $8.3, 7.1, 10.2$. What are $X, Y, Z$?

Similar Questions

Which of the following compounds is obtained when phenol reacts with bromine water?

The reaction sequence is as follows:
$Catechol \xrightarrow{(i) CHCl_3 + KOH}{(ii) CH_2I_2 + NaOH} [X]$
Here $[X]$ is:

Assertion : Reimer-Tiemann reaction of phenol with $CCl_4$ in $NaOH$ at $340 \ K$ gives salicylic acid as the major product. Reason : The reaction occurs through intermediate formation of dichlorocarbene.

Phenol $\xrightarrow{Br_2 / H_2O}$ Product formed is

$C_6H_5OH \xrightarrow{CH_3COCl / NaOH_{(aq)}} C_6H_5OCOCH_3$
The above reaction is an example of which of the following?

Vedclass Test Series

Exam Paper Generator

Online Exam Module