Alcohols Phenols and Ethers Test

Result

Alcohols Phenols and Ethers Test - 32

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Weekly Quiz Competition

Question 1
1 / -0

Maximum boiling point would be shown by:

A
$$\displaystyle { CH }_{ 3 }-O-{ CH }_{ 3 }$$

B
$$\displaystyle { C }_{ 2 }{ H }_{ 5 }-O-{ C }_{ 2 }{ H }_{ 5 }$$

C
$$\displaystyle { CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-OH$$

D
$$\displaystyle ({ CH }_{ 3 }{ ) }_{ 2 }CH-OH$$

Solution

Maximum boiling point would be shown by n propanol, $$\displaystyle { CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-OH$$.
In n-propanol, the molecules are associated due to hydrogen bonding. Hence, the boiling point is higher.
In dimethyl ether and diethyl ether, the boiling point is lower as hydrogen bonding is not possible.
The extent of the hydrogen bonding in isopropanol is lower than that in n-propanol due to +I effect of two methyl groups.
Also, as the degree of branching increases, the boiling point decreases.
Question 2
1 / -0

The correct order of increasing dissociation constant of the following compounds is:

A
II < IV < I < III

B
IV < III < I < II

C
IV < II < I < III

D
IV < I < II < III

Solution

The correct order of increasing dissociation constant of the following compound is $$\displaystyle IV < I < II < III $$.
When electron releasing (activating) -OH substituent is present in phenol,
the dissociation is decreased as the negative charge on the O is intensified. This destablizes the phenoxide ion and the release of proton is not easy. Due to this, the acidity of phenol is decreased.
When electron withdrawing groups (deactivating groups) such as nitro group are present, the acidity of phenols is increased. This is because, the electron withdrawing group disperses the negative charge and facilitates the release of proton. More is the number of nitro substituents, more will be the acidity of phenol.
Also, p nitrophenol is more acidic than o nitro phenol as in o nitro phenol, the removal of proton is difficult as it is hydrogen bonded.
Question 3
1 / -0

For phenol, which of the following statements is correct?

A
It is insoluble in water

B
It has higher boiling point than toluene

C
It does not shows acidic property

D
It has lower melting point compared to aromatic hydrocarbons of comparable molecular weight

Solution

Phenol is sparingly soluble in water.
The boiling point of phenol is higher than the boiling point of toluene due to presence of intermolecular hydrogen bonding in phenol.
Phenol is a weak acid.
It has lower melting point compared to aromatic hydrocarbons of comparable molecular weight.
Thus, only option B is correct.
Question 4
1 / -0

Formation of 2-butene as a major product by dehydration of 2-butanol is according to:

A
Markownikoff rule

B
Saytzeff rule

C
Peroxide effect

D
Anti-markownikoff rule

Solution

The formation of 2-butene as major product by dehydration of 2-butanol is according to Saytzeff rule.
The minor product is 1-butene.
In this reaction, more substituted alkene is obtained as it is more stable.
Question 5
1 / -0

Phenol on reaction with $$\displaystyle { NH }_{ 3 }$$ gives :-

A
Aniline

B
Nitrobenzene

C
Benzaldehyde

D
Anilinium chloride

Solution

Phenol on reaction with ammonia gives aniline. In this reaction, -OH group is replaced with $$-NH_2$$ group.
Question 6
1 / -0

Which of the following is a primary alcohol ?

A
Butan - 2 - ol

B
2 - Methylpropan -1- ol

C
2 - Methylpropan - 2- ol

D
None of the above

Solution

$$CH_{3}-CH(CH_{3})-CH_{2}-OH$$ is a primary alcohol as hydroxal group; -OH is attached to the primary carbon.
Question 7
1 / -0

The major product of the above reaction is:

A

B

C

D

Solution

The major product formed is as given in option D.
Question 8
1 / -0

The order of boiling point of primary (1), secondary (2) and tertiary (3) alcohols is:

A
1 > 2 > 3

B
3 > 2 > 1

C
2 > 1 > 3

D
2 > 3 > 1

Solution

The order of the boiling point is $$ Primary (1)>

secondary (2)> tertiary (3) alcohol$$
This is because the surface area decreases and the van Der waals forces decreases.
Question 9
1 / -0

Carbinol is a trivial name of :-

A
$$\displaystyle { C }_{ 2 }{ H }_{ 5 }OH$$

B
$$\displaystyle { CH }_{ 3 }OH$$

C
$$\displaystyle HCOOH$$

D
$$\displaystyle { CH }_{ 3 }COOH$$

Solution

Carbinol is a trivial name of methanol $$CH_3OH$$.
Question 10
1 / -0

Mark the correct order of decreasing acid strength of the following compounds.

A
e > d > b > a > c

B
b > d > a > c > e

C
d > e > c > b > a

D
e > d > c > b > a

Solution

The correct order of decreasing acid strength is $$ b > d

> a > c > e$$ p-nitrophenol is most acidic and p-methoxy phenol is least acidic. When an electron withdrawing group is para to OH group, the acidity is maximum. When an electron releasing group is para to OH group, the acidity is minimum.