Alcohols Phenols and Ethers Test

Result

Alcohols Phenols and Ethers Test - 31

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Weekly Quiz Competition

Question 1
1 / -0

Butane has a _______ boiling point to that of propanol.

A
higher

B
similar

C
lower

D
none of these

Solution

The molecules of butane are held together by weak vander Waals forces of attraction, while those of propanol are held together by stronger intermolecular hydrogen bonding.
Therefore, the boiling point of propanol is much higher than of butane.
Question 2
1 / -0

Solubility of alcohols in water is _______ to that of hydrocarbons of comparable molecular masses.

A
greater than

B
similar

C
lesser than

D
none of these

Solution

Since alcohols can participate in $$H-$$bonding while hydrocarbons cannot, alcohols are able to interact with water molecules more easily than hydrocarbons of comparable molecular masses. Hence alcohols possess greater solubility in water than hydrocarbons of comparable molecular masses.
Question 3
1 / -0

The IUPAC name of the following compound is:

A
1-cyclopentene-4-ol

B
3-cyclopenten-1-ol

C
3-hydroxy cyclopentene

D
4-hydroxy cyclopentene

Solution
Question 4
1 / -0

When 3-methylbutan-2-ol is treated with HBr, the following reaction takes place. What are the correct steps for formation of the above product?

A
Formation of carbocation $$\rightarrow$$ Nucleophilic attack by $$Br^\ominus$$

B
Formation of carbocation $$\rightarrow$$ 1,2 hydride shift $$\rightarrow$$ Nucleophilic attack by $$Br^\ominus$$

C
Formation of carbocation $$\rightarrow$$ 1,2 methyl shift $$\rightarrow$$ Nucleophilic attack by $$Br^\ominus$$

D
None of these

Solution

The reaction (along with mechanism) for the conversion of 3-methylbutan-2-ol to 2-bromo-2-methylbutane is as given below.
Question 5
1 / -0

The product obtained in the above reaction is:

A

B

C
$$\displaystyle RCH=CHCOOH$$

D
none of these

Solution

When $$\beta$$ hydroxy acid is heated, it undergoes dehydration to form $$\alpha, \beta$$ unsaturated acid.
$$\displaystyle RCHOHCH_2COOH \xrightarrow [dehydration] {\Delta} RCH=CHCOOH$$
Question 6
1 / -0

Consider the reaction between $$\displaystyle C_{2}H_{5}O^{\circleddash }$$ and dimethyl sulphate. The leaving group in this reaction is

A
$$\displaystyle MeOSO_{2}O^{\circleddash }$$

B
$$\displaystyle MeO^{\circleddash }$$

C
$$\displaystyle Me^{\circleddash }$$

D
$$\displaystyle MeOSO_{2}^{\circleddash }$$

Solution
Question 7
1 / -0

The correct reactivity order of alcohols towards $$H-X$$ will be:

A
$$\;II>I>III>IV$$

B
$$\;IV>III>II>I$$

C
$$\;II>IV>I>III$$

D
$$\;II>IV>III>I$$

Solution

The correct reactivity order of alcohols towards H−X will be $$\displaystyle II>IV>III>I $$

Alcohol II has maximum reactivity as the carbocation formed will be stabilized by resonance with adjacent C=C double Bond.

Alcohol I has minimum reactivity as the carbocation formed will have positive charge on $$\displaystyle sp^2$$ carbon atom.

Alcohol IV is more reactive than alcohol III because alcohol IV gives secondary carbocation whereas alcohol III gives primary carbocation.

Secondary carbocation is more stable than primary carbocation.
Question 8
1 / -0

The high boiling point of ethanol $$(78.2^o C)$$ compared to dimethyl ether $$(-23.6^o C)$$, though both having the same molecular formula $$\displaystyle { C }_{ 2 }{ H }_{ 6 }O$$, is due to:

A
hydrogen bonding

B
ionic bonding

C
co-ordinate covalent bonding

D
resonance

Solution

The high boiling point of ethanol $$(78.2 ^oC)$$ compared to dimethyl ether $$(-23.6^oC)$$, though both having the same molecular formula $$C_2H_6O$$, is due to Hydrogen bonding.
Hydrogen bonding is observed when H atom is attached to more electronegative N, F or O atom.
Ethanol molecules are associated due to hydrogen bonding. This results in higher boiling point.
However, hydrogen bonding is not possible in dimethyl ether.
Question 9
1 / -0

In the following dehydration of diol with $$\displaystyle { H }_{ 3 }{ PO }_{ 4 }$$, following product is:

A

B

C

D

Solution

Tertiary alcohol at $$\displaystyle { C }_{ 2 }$$ is more basic than secondary alcohol at $$\displaystyle { C }_{ 5 }$$. Hence, intramolecular dehydration takes place such that H of secondary alcoholic group at $$\displaystyle { C }_{ 5 }$$ eliminates $$\displaystyle OH$$ of tertiary alcoholic group at $$\displaystyle { C }_{ 2 }$$ (with isotopic $$\displaystyle \overset { 18 }{ O } $$) to form a cyclic ether.
Question 10
1 / -0

Heating together of sodium ethoxide and ethyl iodide will give:

A
ether

B
ethyl alcohol

C
acetaldehyde

D
acetic acid

Solution

Williamson's ether synthesis reaction.