Alcohol, Phenol and Ether Test

Result

Alcohol, Phenol and Ether Test - 10

Score
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Rank
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TIME Taken - -

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Weekly Quiz Competition

Question 1
1 / -0

If the boiling point of ethanol (molecular weight = 46 g) is 78°C, what is the boiling point of diethyl ether (molecular weight = 74 g)?

A
100°C

B
78°C

C
86°C

D
34°C

Solution

Ethanol has an -OH group which can involve in hydrogen bonding and diethyl ether molecules don't have such groups, so the boiling point of diethyl ether will be less than that of ethanol.
Question 2
1 / -0

To prepare tert-butyl ethyl ether by Williamson's synthesis, the reactants needed are

A
sodium ethoxide and sodium tert butoxide

B
sodium ethoxide and tert-butyl bromide

C
sodium tert-butoxide and ethyl bromide

D
ethyl alcohol and tert-butyl alcohol

Solution

1° alkyl halides, on treatment with an alkoxide ion, tend to undergo substitution to form ethers. Thus, sodium tert-butoxide and ethyl bromide form the right pair of reagents, i.e.
(CH₃)₃CO^-Na⁺ + CH₃CH₂Br → (CH₃)₃C-O-CH₂CH₃ + NaBr
Question 3
1 / -0

Which of the following has the highest boiling point?

A
Dimethyl ether

B
Diethyl ether

C
n-hexane

D
n-pentane

Solution

Due to the weak dipole-dipole interactions, the boiling points of dimethyl ether and ethyl methyl ether etc. are lower than those of n-alkanes of comparable molecular masses. However, as the hydrocarbon part increases beyond four carbon atoms, the boiling points of ethers becomes slightly higher than those of n-alkanes of comparable molecular masses.
Question 4
1 / -0

The major products formed when the following ether is heated with conc. HI are

CH₃CH₂CH₂-O-C(CH₃)₂CH₂CH₃

A
CH₃CH₂CH₂I + HO-C(CH₃)₂CH₂CH₃

B
CH₃CH₂CH₂OH + I-C(CH₃)₂CH₂CH₃

C
CH₃CH₂CH₂I + I-C(CH₃)₂CH₂CH₃

D
CH₃CH₂CH₂OH + (CH₃)₂C=CHCH₃

Solution

The high polarity of the solvent (H₂O) present in conc. HI (57 %) favours S_N1 mechanism and hence, I^- ion attacks the carbocation CH₃CH₂(CH₃)₂C⁺ giving CH₃CH₂C(CH₃)₂I as the alkyl halide.