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CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323269 Arrange the following compounds in the increasing order of their acidic strength
(i) m-Nitrophenol
(ii) $m$ -Cresol
(iii) Phenol
(iv) $m$ -Chlorophenol

1 ii

<

iv

<

iii

<

2 i

i < iii < i < iv

3 iii

< ii < i < iv

4 ii

<

iii

<

iv

<

i

Explanation:

supporting img
Nitro group has both -R effect and -I effect, but $- R$ effect predominates. Due to stronger electron withdrawing
nature of $- {NO}_{2}$ group, phenoxide ion is stablized more. Hence nitrophenol is more acidic than phenol.
Methyl group destabilizes the phenoxide ion by $+ i$ effect and hyperconjugation.
Hence m-cresol is weaker acid than phenol.
Chlorine have both $+ R$ and $- I$ effect but $- I$ effect predominates. Hence $m$ -chlorophenol is more acidic than phenol.
- $R$ effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than $m$ - chlorophenol. Therefore the correct order of acidic strength is
$\underset{(i)}{m - nitrophenol >} \underset{(iv)}{m - chlorophenol >} \underset{(iii)}{phenol >} \underset{(ii)}{m - cresol}$

KCET - 2015

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323270 Among the following, which is least acidic?

1 p-Nitrophenol

2 p-Chlorophenol

3 Phenol

4 o-Cresol

Explanation:

supporting img
Electron with drawing group $(- {NO}_{2}, - Cl)$ decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group $(- {CH}_{3})$ decreases the acidic character by increasing the electron density in the ring.

KCET - 2008

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323271 Assertion :
Phenols do not react with carbonates and bicarbonates.
Reason :
On aerial oxidation phenol gives pink coloured phenoquinone.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Phenols, with a $K_{a}$ range of $10^{- 10}$ to $10^{- 15}$ are weaker acids compared to carboxylic acids and carbonic acids, resulting in reduced reactivity with carbonates and bicarbonates. So the option (2) is correct.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323272 Mark the correct order of decreasing acid strength of the following compounds.
supporting img

1 I

>

II

>

III

2 III

>

I

>

II

3 III

>

II

>

I

4 II

>

III

>

I

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323269 Arrange the following compounds in the increasing order of their acidic strength
(i) m-Nitrophenol
(ii) $m$ -Cresol
(iii) Phenol
(iv) $m$ -Chlorophenol

1 ii

<

iv

<

iii

<

2 i

i < iii < i < iv

3 iii

< ii < i < iv

4 ii

<

iii

<

iv

<

i

Explanation:

supporting img
Nitro group has both -R effect and -I effect, but $- R$ effect predominates. Due to stronger electron withdrawing
nature of $- {NO}_{2}$ group, phenoxide ion is stablized more. Hence nitrophenol is more acidic than phenol.
Methyl group destabilizes the phenoxide ion by $+ i$ effect and hyperconjugation.
Hence m-cresol is weaker acid than phenol.
Chlorine have both $+ R$ and $- I$ effect but $- I$ effect predominates. Hence $m$ -chlorophenol is more acidic than phenol.
- $R$ effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than $m$ - chlorophenol. Therefore the correct order of acidic strength is
$\underset{(i)}{m - nitrophenol >} \underset{(iv)}{m - chlorophenol >} \underset{(iii)}{phenol >} \underset{(ii)}{m - cresol}$

KCET - 2015

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323270 Among the following, which is least acidic?

1 p-Nitrophenol

2 p-Chlorophenol

3 Phenol

4 o-Cresol

Explanation:

supporting img
Electron with drawing group $(- {NO}_{2}, - Cl)$ decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group $(- {CH}_{3})$ decreases the acidic character by increasing the electron density in the ring.

KCET - 2008

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323271 Assertion :
Phenols do not react with carbonates and bicarbonates.
Reason :
On aerial oxidation phenol gives pink coloured phenoquinone.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Phenols, with a $K_{a}$ range of $10^{- 10}$ to $10^{- 15}$ are weaker acids compared to carboxylic acids and carbonic acids, resulting in reduced reactivity with carbonates and bicarbonates. So the option (2) is correct.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323272 Mark the correct order of decreasing acid strength of the following compounds.
supporting img

1 I

>

II

>

III

2 III

>

I

>

II

3 III

>

II

>

I

4 II

>

III

>

I

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323269 Arrange the following compounds in the increasing order of their acidic strength
(i) m-Nitrophenol
(ii) $m$ -Cresol
(iii) Phenol
(iv) $m$ -Chlorophenol

1 ii

<

iv

<

iii

<

2 i

i < iii < i < iv

3 iii

< ii < i < iv

4 ii

<

iii

<

iv

<

i

Explanation:

supporting img
Nitro group has both -R effect and -I effect, but $- R$ effect predominates. Due to stronger electron withdrawing
nature of $- {NO}_{2}$ group, phenoxide ion is stablized more. Hence nitrophenol is more acidic than phenol.
Methyl group destabilizes the phenoxide ion by $+ i$ effect and hyperconjugation.
Hence m-cresol is weaker acid than phenol.
Chlorine have both $+ R$ and $- I$ effect but $- I$ effect predominates. Hence $m$ -chlorophenol is more acidic than phenol.
- $R$ effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than $m$ - chlorophenol. Therefore the correct order of acidic strength is
$\underset{(i)}{m - nitrophenol >} \underset{(iv)}{m - chlorophenol >} \underset{(iii)}{phenol >} \underset{(ii)}{m - cresol}$

KCET - 2015

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323270 Among the following, which is least acidic?

1 p-Nitrophenol

2 p-Chlorophenol

3 Phenol

4 o-Cresol

Explanation:

supporting img
Electron with drawing group $(- {NO}_{2}, - Cl)$ decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group $(- {CH}_{3})$ decreases the acidic character by increasing the electron density in the ring.

KCET - 2008

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323271 Assertion :
Phenols do not react with carbonates and bicarbonates.
Reason :
On aerial oxidation phenol gives pink coloured phenoquinone.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Phenols, with a $K_{a}$ range of $10^{- 10}$ to $10^{- 15}$ are weaker acids compared to carboxylic acids and carbonic acids, resulting in reduced reactivity with carbonates and bicarbonates. So the option (2) is correct.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323272 Mark the correct order of decreasing acid strength of the following compounds.
supporting img

1 I

>

II

>

III

2 III

>

I

>

II

3 III

>

II

>

I

4 II

>

III

>

I

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323269 Arrange the following compounds in the increasing order of their acidic strength
(i) m-Nitrophenol
(ii) $m$ -Cresol
(iii) Phenol
(iv) $m$ -Chlorophenol

1 ii

<

iv

<

iii

<

2 i

i < iii < i < iv

3 iii

< ii < i < iv

4 ii

<

iii

<

iv

<

i

Explanation:

supporting img
Nitro group has both -R effect and -I effect, but $- R$ effect predominates. Due to stronger electron withdrawing
nature of $- {NO}_{2}$ group, phenoxide ion is stablized more. Hence nitrophenol is more acidic than phenol.
Methyl group destabilizes the phenoxide ion by $+ i$ effect and hyperconjugation.
Hence m-cresol is weaker acid than phenol.
Chlorine have both $+ R$ and $- I$ effect but $- I$ effect predominates. Hence $m$ -chlorophenol is more acidic than phenol.
- $R$ effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than $m$ - chlorophenol. Therefore the correct order of acidic strength is
$\underset{(i)}{m - nitrophenol >} \underset{(iv)}{m - chlorophenol >} \underset{(iii)}{phenol >} \underset{(ii)}{m - cresol}$

KCET - 2015

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323270 Among the following, which is least acidic?

1 p-Nitrophenol

2 p-Chlorophenol

3 Phenol

4 o-Cresol

Explanation:

supporting img
Electron with drawing group $(- {NO}_{2}, - Cl)$ decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group $(- {CH}_{3})$ decreases the acidic character by increasing the electron density in the ring.

KCET - 2008

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323271 Assertion :
Phenols do not react with carbonates and bicarbonates.
Reason :
On aerial oxidation phenol gives pink coloured phenoquinone.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Phenols, with a $K_{a}$ range of $10^{- 10}$ to $10^{- 15}$ are weaker acids compared to carboxylic acids and carbonic acids, resulting in reduced reactivity with carbonates and bicarbonates. So the option (2) is correct.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323272 Mark the correct order of decreasing acid strength of the following compounds.
supporting img

1 I

>

II

>

III

2 III

>

I

>

II

3 III

>

II

>

I

4 II

>

III

>

I