Alcohols Phenols and Ethers Test

Result

Alcohols Phenols and Ethers Test - 10

Score
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out of -
Rank
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TIME Taken - -

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following compounds will react with sodium hydroxide solution in water?

A
C₆H₅OH

B
C₆H₅CH₂OH

C
C₂H₅OH

D
(CH₃)₃COH

Solution

Phenol is more soluble in NaOH than in water is because phenol is slightly more acidic than alcohols. The Ka for phenol in water is 1e-10 which is not very strong. But by mixing with NaOH, it causes the phenol to release the H+ to form sodium phenoxide.
Question 2
1 / -0

Phenol is less acidic than ______________.

A
o – nitrophenol

B
o – methoxyphenol

C
o – methylphenol

D
ethanol

Solution

The nitro-group is an electron-withdrawing group. The presence of this group in the ortho or para position decreases the electron density in the OH bond. As a result, it is easier to lose a proton. Also, the o-nitrophenoxide or p-nitrophenoxide ion formed after the loss of protons is stabilized by resonance. Hence, ortho and para nitrophenols are stronger acids than phenol.
Question 3
1 / -0

Which of the following is most acidic?

A
Benzyl alcohol

B
Phenol

C
Cyclohexanol

D
m – Chlorophenol

Solution

In cases of halogen derivatives of phenols or aniline or benzoic acid etc, it is very helpful to understand that all halogens, when attached to benzene ring, exerts -I as well as +R effect.

In case of Cl, Br and I, the +R effect has almost no effect on reactivity, acidic character or basic character of the benzene ring. It is due to very less effective overlapping involving 2p of carbon and 3p or 4p or 5p of halogen.

Hence, only -I effect becomes the deciding factor, which is most dominant from ortho-position and least effective from para-position. So m chlorophenol is most acidic.