Most Asked Questions
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Alcohols, Phenols And Ethers

- Get to know usually which areas are frequently asked in the NEET examination
1

Phenol from cumene

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Cumene on reaction with oxygen followed by hydrolysis gives:
A
and
B
and
C
and
D
and
Cumene process is the most important commercial method for the manufacture of phenol. Cumene is:
A
methyl ethyl benzene
B
ethyl benzene
C
vinyl benzene
D
propyl benzene
2

Reaction between ethers and halogens acids

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Ethers are easily cleaved by hydroiodic acid or hydrobromic acid.

The cleavage of C-O bond in ethers takes place under drastic conditions with excess of hydrogen halides. The reaction of dialkyl ether gives two alkyl halide molecules.

Alkyl aryl ethers are cleaved at the alkyl-oxygen bond due to the more stable aryl-oxygen bond. The reaction yields phenol and alkyl halide.

What are the products when ethyl isopropyl ether is cleaved with concentrated ?
A
Ethanol and 2-iodo-2-methyl propane
B
Ethanol and 2-methyl propane
C
Iodoethane and isopropyl alcohol
D
Iodoethane and 2-methyl propane
Which pair of products would result from the acid cleavage of phenyl propyl ether with excess concentrated ?
A
Phenol and 1-propanol
B
Bromobenzene and 1-propanol
C
Bromobenzene and 1-bromopropane
D
Phenol and 1-bromopropane
3

Acidic strength of nitrophenols

1. The acidic nature of the three nitrophenols increases in the order: meta < ortho < para.
2. Para nitorophenol is the most acidic among the three. 
3. The nitro group attached to a conjugated system shows strong -M effect, and this decreases the electron density more at the ortho and para positions than at the meta position.
4.  This factor helps greater stabilization of the conjugate base (nitro phenoxide ion) of the ortho and para isomers than that of the meta isomer.
5.  So, meta nitrophenol is the weakest in terms of acidity.
In the compounds shown above, the correct order of acidity is  :
A
I > IV > III > II
B
II > IV > I > II
C
II > I > III > IV
D
IV > III > I > II