323052
Read Assertion and Reason carefully and mark correct option. Assertion : Butan –1– ol has higher boiling point than ethoxyethane. Reason : Extensive hydrogen bonding leads to stronger association of molecules.
1 Assertion is false but Reason is true
2 Assertion is true but Reason is false
3 Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
4 Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Explanation:
Alcohols have higher boiling point than ethers due to the hydrogen bonding. These hydrogen bonding help in intermolecular association.
JEE - 2023
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323053
The increasing order of boiling points of the below mentioned alcohols is I. 1, 2-dihydroxybenzene II. 1, 3-dihydroxybenzene III. 1, 4-dihydroxybenzene IV. Hydroxybenzene
1 IV \( < \) II \( < \) I \( < \) III
2 IV \( < \) I \( < \) II \( < \) III
3 I \( < \) II \( < \) IV \( < \) III
4 I \( < \) II \( < \) III \( < \) IV
Explanation:
Among the given compounds, hydroxybenzene (IV) has least molar mass and therefore possess least boiling. 1, 2dihydroxybenzene (I) forms intramolecular \(\mathrm{H}\)- bonding with result that it will not form intermolecular H-bonding leading to lowest boiling point. On the other hand 1, 3dihydroxybenzene (II) and 1, 4dihydroxybenzene (III) does not undergo chelation, hence they will involve extensive intermolecular \(\mathrm{H}\)-bonding leading to higher boiling point. Further intermolecular hydrogen bonding is stronger in the p-isomer than the \(\mathrm{m}\)- isomer hence former has highest b.p. Thus the decreasing order of boiling points is III \(>\) II \(>\) I \(>\) IV.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323054
Which of the following alcohols has lowest boiling point?
1 sec-Butyl alcohol
2 tert-Butyl alcohol
3 iso- Butyl alcohol
4 n-Butyl alcohol
Explanation:
As branching increases, boiling point decreases. \(\therefore\) tert-butyl alcohol has lowest boiling point, due to minimum surface area.
MHTCET - 2021
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323055
What is the predominant reason why 1 -propanol has a higher B.P. than 1-propanthiol?
1 Molecules with less surface area can pack more closely, making them harder to boil.
2 1-propanthiol is more polar than 1-propanol
3 The greater polarity of O-H bond allows \(\mathrm{H}\)-bonding to increase the attractive forces between 1-propanol molecules
4 The longer S-H bond makes 1-propanthiol less stable than 1-propanol
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CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323052
Read Assertion and Reason carefully and mark correct option. Assertion : Butan –1– ol has higher boiling point than ethoxyethane. Reason : Extensive hydrogen bonding leads to stronger association of molecules.
1 Assertion is false but Reason is true
2 Assertion is true but Reason is false
3 Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
4 Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Explanation:
Alcohols have higher boiling point than ethers due to the hydrogen bonding. These hydrogen bonding help in intermolecular association.
JEE - 2023
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323053
The increasing order of boiling points of the below mentioned alcohols is I. 1, 2-dihydroxybenzene II. 1, 3-dihydroxybenzene III. 1, 4-dihydroxybenzene IV. Hydroxybenzene
1 IV \( < \) II \( < \) I \( < \) III
2 IV \( < \) I \( < \) II \( < \) III
3 I \( < \) II \( < \) IV \( < \) III
4 I \( < \) II \( < \) III \( < \) IV
Explanation:
Among the given compounds, hydroxybenzene (IV) has least molar mass and therefore possess least boiling. 1, 2dihydroxybenzene (I) forms intramolecular \(\mathrm{H}\)- bonding with result that it will not form intermolecular H-bonding leading to lowest boiling point. On the other hand 1, 3dihydroxybenzene (II) and 1, 4dihydroxybenzene (III) does not undergo chelation, hence they will involve extensive intermolecular \(\mathrm{H}\)-bonding leading to higher boiling point. Further intermolecular hydrogen bonding is stronger in the p-isomer than the \(\mathrm{m}\)- isomer hence former has highest b.p. Thus the decreasing order of boiling points is III \(>\) II \(>\) I \(>\) IV.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323054
Which of the following alcohols has lowest boiling point?
1 sec-Butyl alcohol
2 tert-Butyl alcohol
3 iso- Butyl alcohol
4 n-Butyl alcohol
Explanation:
As branching increases, boiling point decreases. \(\therefore\) tert-butyl alcohol has lowest boiling point, due to minimum surface area.
MHTCET - 2021
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323055
What is the predominant reason why 1 -propanol has a higher B.P. than 1-propanthiol?
1 Molecules with less surface area can pack more closely, making them harder to boil.
2 1-propanthiol is more polar than 1-propanol
3 The greater polarity of O-H bond allows \(\mathrm{H}\)-bonding to increase the attractive forces between 1-propanol molecules
4 The longer S-H bond makes 1-propanthiol less stable than 1-propanol
323052
Read Assertion and Reason carefully and mark correct option. Assertion : Butan –1– ol has higher boiling point than ethoxyethane. Reason : Extensive hydrogen bonding leads to stronger association of molecules.
1 Assertion is false but Reason is true
2 Assertion is true but Reason is false
3 Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
4 Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Explanation:
Alcohols have higher boiling point than ethers due to the hydrogen bonding. These hydrogen bonding help in intermolecular association.
JEE - 2023
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323053
The increasing order of boiling points of the below mentioned alcohols is I. 1, 2-dihydroxybenzene II. 1, 3-dihydroxybenzene III. 1, 4-dihydroxybenzene IV. Hydroxybenzene
1 IV \( < \) II \( < \) I \( < \) III
2 IV \( < \) I \( < \) II \( < \) III
3 I \( < \) II \( < \) IV \( < \) III
4 I \( < \) II \( < \) III \( < \) IV
Explanation:
Among the given compounds, hydroxybenzene (IV) has least molar mass and therefore possess least boiling. 1, 2dihydroxybenzene (I) forms intramolecular \(\mathrm{H}\)- bonding with result that it will not form intermolecular H-bonding leading to lowest boiling point. On the other hand 1, 3dihydroxybenzene (II) and 1, 4dihydroxybenzene (III) does not undergo chelation, hence they will involve extensive intermolecular \(\mathrm{H}\)-bonding leading to higher boiling point. Further intermolecular hydrogen bonding is stronger in the p-isomer than the \(\mathrm{m}\)- isomer hence former has highest b.p. Thus the decreasing order of boiling points is III \(>\) II \(>\) I \(>\) IV.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323054
Which of the following alcohols has lowest boiling point?
1 sec-Butyl alcohol
2 tert-Butyl alcohol
3 iso- Butyl alcohol
4 n-Butyl alcohol
Explanation:
As branching increases, boiling point decreases. \(\therefore\) tert-butyl alcohol has lowest boiling point, due to minimum surface area.
MHTCET - 2021
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323055
What is the predominant reason why 1 -propanol has a higher B.P. than 1-propanthiol?
1 Molecules with less surface area can pack more closely, making them harder to boil.
2 1-propanthiol is more polar than 1-propanol
3 The greater polarity of O-H bond allows \(\mathrm{H}\)-bonding to increase the attractive forces between 1-propanol molecules
4 The longer S-H bond makes 1-propanthiol less stable than 1-propanol
323052
Read Assertion and Reason carefully and mark correct option. Assertion : Butan –1– ol has higher boiling point than ethoxyethane. Reason : Extensive hydrogen bonding leads to stronger association of molecules.
1 Assertion is false but Reason is true
2 Assertion is true but Reason is false
3 Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
4 Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Explanation:
Alcohols have higher boiling point than ethers due to the hydrogen bonding. These hydrogen bonding help in intermolecular association.
JEE - 2023
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323053
The increasing order of boiling points of the below mentioned alcohols is I. 1, 2-dihydroxybenzene II. 1, 3-dihydroxybenzene III. 1, 4-dihydroxybenzene IV. Hydroxybenzene
1 IV \( < \) II \( < \) I \( < \) III
2 IV \( < \) I \( < \) II \( < \) III
3 I \( < \) II \( < \) IV \( < \) III
4 I \( < \) II \( < \) III \( < \) IV
Explanation:
Among the given compounds, hydroxybenzene (IV) has least molar mass and therefore possess least boiling. 1, 2dihydroxybenzene (I) forms intramolecular \(\mathrm{H}\)- bonding with result that it will not form intermolecular H-bonding leading to lowest boiling point. On the other hand 1, 3dihydroxybenzene (II) and 1, 4dihydroxybenzene (III) does not undergo chelation, hence they will involve extensive intermolecular \(\mathrm{H}\)-bonding leading to higher boiling point. Further intermolecular hydrogen bonding is stronger in the p-isomer than the \(\mathrm{m}\)- isomer hence former has highest b.p. Thus the decreasing order of boiling points is III \(>\) II \(>\) I \(>\) IV.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323054
Which of the following alcohols has lowest boiling point?
1 sec-Butyl alcohol
2 tert-Butyl alcohol
3 iso- Butyl alcohol
4 n-Butyl alcohol
Explanation:
As branching increases, boiling point decreases. \(\therefore\) tert-butyl alcohol has lowest boiling point, due to minimum surface area.
MHTCET - 2021
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323055
What is the predominant reason why 1 -propanol has a higher B.P. than 1-propanthiol?
1 Molecules with less surface area can pack more closely, making them harder to boil.
2 1-propanthiol is more polar than 1-propanol
3 The greater polarity of O-H bond allows \(\mathrm{H}\)-bonding to increase the attractive forces between 1-propanol molecules
4 The longer S-H bond makes 1-propanthiol less stable than 1-propanol