323171
When alcohol reacts with conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\), intermediate compound formed is
1 carbonium ion
2 alkoxy ion
3 alkyl hydrogen sulphate
4 None of the above
Explanation:
Conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is an excellent dehydrating agent. Upon reaction with an alcohol, it forms an alkene and water molecule is given out. First step involves protonation of alcohol.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323172
The order of reactivity of the following alcohols towards conc. \(\mathrm{HCl}\) is
1 I \(>\) II \(>\) III \(>\) IV
2 I \(>\) III \(>\) II \(>\) IV
3 IV \(>\) III \(>\) II \(>\) I
4 IV \(>\) III \(>\) I \(>\) II
Explanation:
From (IV). \(1^{\circ}\), Most stable benzyl carbocation Remember that presence of electron-withdrawing intensifies i.e., destabilises the carbocation thus (I) and (II) are less stable than (III). Further (I) is less stable than (II) because - I effect is more pronounced in (I) due to less distance between \(\mathrm{F}\) and + charge. Reactivity of their parent alcohols will be IV \(>\) III \(>\) II \(>\) I.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323173
Decreasing order of reactivity of hydrogen halide acid in the conversion of \({\rm{ROH}} \to {\rm{RX}}\) is
\(\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}>\mathrm{HF}\).This is due to the fact that, nucleophilicity of a halide ion increases with increase in size. As the size of halide ion increases from \(\mathrm{F}^{\ominus}\) to \(\mathrm{I}^{\ominus}\), thus, \(\mathrm{I}^{-}\)ion will be a better nucleophile followed by \(\mathrm{Br}^{-}, \mathrm{Cl}^{-}\)and \(\mathrm{F}^{-}\).
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323174
In the esterification reaction, the correct order of reactivity of alcohols is
During esterification reaction, alcohol loses \(\mathrm{H}^{+}\)which explains its acidic character. Stronger is the acid less tendency to undergo esterification. So, the order is \(\mathrm{CH}_{3} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHOH}\)
323171
When alcohol reacts with conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\), intermediate compound formed is
1 carbonium ion
2 alkoxy ion
3 alkyl hydrogen sulphate
4 None of the above
Explanation:
Conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is an excellent dehydrating agent. Upon reaction with an alcohol, it forms an alkene and water molecule is given out. First step involves protonation of alcohol.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323172
The order of reactivity of the following alcohols towards conc. \(\mathrm{HCl}\) is
1 I \(>\) II \(>\) III \(>\) IV
2 I \(>\) III \(>\) II \(>\) IV
3 IV \(>\) III \(>\) II \(>\) I
4 IV \(>\) III \(>\) I \(>\) II
Explanation:
From (IV). \(1^{\circ}\), Most stable benzyl carbocation Remember that presence of electron-withdrawing intensifies i.e., destabilises the carbocation thus (I) and (II) are less stable than (III). Further (I) is less stable than (II) because - I effect is more pronounced in (I) due to less distance between \(\mathrm{F}\) and + charge. Reactivity of their parent alcohols will be IV \(>\) III \(>\) II \(>\) I.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323173
Decreasing order of reactivity of hydrogen halide acid in the conversion of \({\rm{ROH}} \to {\rm{RX}}\) is
\(\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}>\mathrm{HF}\).This is due to the fact that, nucleophilicity of a halide ion increases with increase in size. As the size of halide ion increases from \(\mathrm{F}^{\ominus}\) to \(\mathrm{I}^{\ominus}\), thus, \(\mathrm{I}^{-}\)ion will be a better nucleophile followed by \(\mathrm{Br}^{-}, \mathrm{Cl}^{-}\)and \(\mathrm{F}^{-}\).
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323174
In the esterification reaction, the correct order of reactivity of alcohols is
During esterification reaction, alcohol loses \(\mathrm{H}^{+}\)which explains its acidic character. Stronger is the acid less tendency to undergo esterification. So, the order is \(\mathrm{CH}_{3} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHOH}\)
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CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323171
When alcohol reacts with conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\), intermediate compound formed is
1 carbonium ion
2 alkoxy ion
3 alkyl hydrogen sulphate
4 None of the above
Explanation:
Conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is an excellent dehydrating agent. Upon reaction with an alcohol, it forms an alkene and water molecule is given out. First step involves protonation of alcohol.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323172
The order of reactivity of the following alcohols towards conc. \(\mathrm{HCl}\) is
1 I \(>\) II \(>\) III \(>\) IV
2 I \(>\) III \(>\) II \(>\) IV
3 IV \(>\) III \(>\) II \(>\) I
4 IV \(>\) III \(>\) I \(>\) II
Explanation:
From (IV). \(1^{\circ}\), Most stable benzyl carbocation Remember that presence of electron-withdrawing intensifies i.e., destabilises the carbocation thus (I) and (II) are less stable than (III). Further (I) is less stable than (II) because - I effect is more pronounced in (I) due to less distance between \(\mathrm{F}\) and + charge. Reactivity of their parent alcohols will be IV \(>\) III \(>\) II \(>\) I.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323173
Decreasing order of reactivity of hydrogen halide acid in the conversion of \({\rm{ROH}} \to {\rm{RX}}\) is
\(\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}>\mathrm{HF}\).This is due to the fact that, nucleophilicity of a halide ion increases with increase in size. As the size of halide ion increases from \(\mathrm{F}^{\ominus}\) to \(\mathrm{I}^{\ominus}\), thus, \(\mathrm{I}^{-}\)ion will be a better nucleophile followed by \(\mathrm{Br}^{-}, \mathrm{Cl}^{-}\)and \(\mathrm{F}^{-}\).
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323174
In the esterification reaction, the correct order of reactivity of alcohols is
During esterification reaction, alcohol loses \(\mathrm{H}^{+}\)which explains its acidic character. Stronger is the acid less tendency to undergo esterification. So, the order is \(\mathrm{CH}_{3} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHOH}\)
323171
When alcohol reacts with conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\), intermediate compound formed is
1 carbonium ion
2 alkoxy ion
3 alkyl hydrogen sulphate
4 None of the above
Explanation:
Conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is an excellent dehydrating agent. Upon reaction with an alcohol, it forms an alkene and water molecule is given out. First step involves protonation of alcohol.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323172
The order of reactivity of the following alcohols towards conc. \(\mathrm{HCl}\) is
1 I \(>\) II \(>\) III \(>\) IV
2 I \(>\) III \(>\) II \(>\) IV
3 IV \(>\) III \(>\) II \(>\) I
4 IV \(>\) III \(>\) I \(>\) II
Explanation:
From (IV). \(1^{\circ}\), Most stable benzyl carbocation Remember that presence of electron-withdrawing intensifies i.e., destabilises the carbocation thus (I) and (II) are less stable than (III). Further (I) is less stable than (II) because - I effect is more pronounced in (I) due to less distance between \(\mathrm{F}\) and + charge. Reactivity of their parent alcohols will be IV \(>\) III \(>\) II \(>\) I.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323173
Decreasing order of reactivity of hydrogen halide acid in the conversion of \({\rm{ROH}} \to {\rm{RX}}\) is
\(\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}>\mathrm{HF}\).This is due to the fact that, nucleophilicity of a halide ion increases with increase in size. As the size of halide ion increases from \(\mathrm{F}^{\ominus}\) to \(\mathrm{I}^{\ominus}\), thus, \(\mathrm{I}^{-}\)ion will be a better nucleophile followed by \(\mathrm{Br}^{-}, \mathrm{Cl}^{-}\)and \(\mathrm{F}^{-}\).
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323174
In the esterification reaction, the correct order of reactivity of alcohols is
During esterification reaction, alcohol loses \(\mathrm{H}^{+}\)which explains its acidic character. Stronger is the acid less tendency to undergo esterification. So, the order is \(\mathrm{CH}_{3} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHOH}\)
