323269
Arrange the following compounds in the increasing order of their acidic strength (i) m-Nitrophenol (ii) \(\mathrm{m}\)-Cresol (iii) Phenol (iv) \(\mathrm{m}\)-Chlorophenol
1 ii \( < \) iv \( < \) iii \( < \)
2 i \(\mathrm{i} < \mathrm{iii} < \mathrm{i} < \mathrm{iv}\)
3 iii \( < \mathrm{ii} < \mathrm{i} < \mathrm{iv}\)
4 ii \( < \) iii \( < \) iv \( < \) i
Explanation:
Nitro group has both -R effect and -I effect, but \(-R\) effect predominates. Due to stronger electron withdrawing nature of \(-\mathrm{NO}_{2}\) 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 \(+\mathrm{R}\) and \(-\mathrm{I}\) effect but \(-\mathrm{I}\) effect predominates. Hence \(\mathrm{m}\)-chlorophenol is more acidic than phenol. - \(\mathrm{R}\) effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than \(\mathrm{m}\) - chlorophenol. Therefore the correct order of acidic strength is \(\mathop {{\text{m - nitrophenol}} > }\limits_{{\text{(i)}}} \,\mathop {{\text{m - chlorophenol}} > }\limits_{{\text{(iv)}}} \,\mathop {{\text{phenol}} > \,}\limits_{{\text{(iii)}}} \mathop {{\text{m - cresol}}}\limits_{{\text{(ii)}}} \)
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:
Electron with drawing group \(\left(-\mathrm{NO}_{2},-\mathrm{Cl}\right)\) decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group \(\left(-\mathrm{CH}_{3}\right)\) 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.
323269
Arrange the following compounds in the increasing order of their acidic strength (i) m-Nitrophenol (ii) \(\mathrm{m}\)-Cresol (iii) Phenol (iv) \(\mathrm{m}\)-Chlorophenol
1 ii \( < \) iv \( < \) iii \( < \)
2 i \(\mathrm{i} < \mathrm{iii} < \mathrm{i} < \mathrm{iv}\)
3 iii \( < \mathrm{ii} < \mathrm{i} < \mathrm{iv}\)
4 ii \( < \) iii \( < \) iv \( < \) i
Explanation:
Nitro group has both -R effect and -I effect, but \(-R\) effect predominates. Due to stronger electron withdrawing nature of \(-\mathrm{NO}_{2}\) 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 \(+\mathrm{R}\) and \(-\mathrm{I}\) effect but \(-\mathrm{I}\) effect predominates. Hence \(\mathrm{m}\)-chlorophenol is more acidic than phenol. - \(\mathrm{R}\) effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than \(\mathrm{m}\) - chlorophenol. Therefore the correct order of acidic strength is \(\mathop {{\text{m - nitrophenol}} > }\limits_{{\text{(i)}}} \,\mathop {{\text{m - chlorophenol}} > }\limits_{{\text{(iv)}}} \,\mathop {{\text{phenol}} > \,}\limits_{{\text{(iii)}}} \mathop {{\text{m - cresol}}}\limits_{{\text{(ii)}}} \)
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:
Electron with drawing group \(\left(-\mathrm{NO}_{2},-\mathrm{Cl}\right)\) decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group \(\left(-\mathrm{CH}_{3}\right)\) 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.
323269
Arrange the following compounds in the increasing order of their acidic strength (i) m-Nitrophenol (ii) \(\mathrm{m}\)-Cresol (iii) Phenol (iv) \(\mathrm{m}\)-Chlorophenol
1 ii \( < \) iv \( < \) iii \( < \)
2 i \(\mathrm{i} < \mathrm{iii} < \mathrm{i} < \mathrm{iv}\)
3 iii \( < \mathrm{ii} < \mathrm{i} < \mathrm{iv}\)
4 ii \( < \) iii \( < \) iv \( < \) i
Explanation:
Nitro group has both -R effect and -I effect, but \(-R\) effect predominates. Due to stronger electron withdrawing nature of \(-\mathrm{NO}_{2}\) 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 \(+\mathrm{R}\) and \(-\mathrm{I}\) effect but \(-\mathrm{I}\) effect predominates. Hence \(\mathrm{m}\)-chlorophenol is more acidic than phenol. - \(\mathrm{R}\) effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than \(\mathrm{m}\) - chlorophenol. Therefore the correct order of acidic strength is \(\mathop {{\text{m - nitrophenol}} > }\limits_{{\text{(i)}}} \,\mathop {{\text{m - chlorophenol}} > }\limits_{{\text{(iv)}}} \,\mathop {{\text{phenol}} > \,}\limits_{{\text{(iii)}}} \mathop {{\text{m - cresol}}}\limits_{{\text{(ii)}}} \)
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:
Electron with drawing group \(\left(-\mathrm{NO}_{2},-\mathrm{Cl}\right)\) decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group \(\left(-\mathrm{CH}_{3}\right)\) 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.
323269
Arrange the following compounds in the increasing order of their acidic strength (i) m-Nitrophenol (ii) \(\mathrm{m}\)-Cresol (iii) Phenol (iv) \(\mathrm{m}\)-Chlorophenol
1 ii \( < \) iv \( < \) iii \( < \)
2 i \(\mathrm{i} < \mathrm{iii} < \mathrm{i} < \mathrm{iv}\)
3 iii \( < \mathrm{ii} < \mathrm{i} < \mathrm{iv}\)
4 ii \( < \) iii \( < \) iv \( < \) i
Explanation:
Nitro group has both -R effect and -I effect, but \(-R\) effect predominates. Due to stronger electron withdrawing nature of \(-\mathrm{NO}_{2}\) 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 \(+\mathrm{R}\) and \(-\mathrm{I}\) effect but \(-\mathrm{I}\) effect predominates. Hence \(\mathrm{m}\)-chlorophenol is more acidic than phenol. - \(\mathrm{R}\) effect of nitro group is stronger than -I effect of chlorine, hence m- nitrophenol is more acidic than \(\mathrm{m}\) - chlorophenol. Therefore the correct order of acidic strength is \(\mathop {{\text{m - nitrophenol}} > }\limits_{{\text{(i)}}} \,\mathop {{\text{m - chlorophenol}} > }\limits_{{\text{(iv)}}} \,\mathop {{\text{phenol}} > \,}\limits_{{\text{(iii)}}} \mathop {{\text{m - cresol}}}\limits_{{\text{(ii)}}} \)
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:
Electron with drawing group \(\left(-\mathrm{NO}_{2},-\mathrm{Cl}\right)\) decreases the electron density in the ring and thus increases their acidic character whereas electron donating acidic character whereas electron donating group \(\left(-\mathrm{CH}_{3}\right)\) 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.
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