Alcohols Phenols and Ethers - Online Test

Answer : Option B
Explaination / Solution:

The rate of dehydration is related to the ease of formation of Carbocation and the energy of the carbocation intermediate. -.

Dehydration involves formation of carbocation 1^st and since tertiary carbocation is more stable than secondary and primary therefore 3° is dehydrated first.

The ease of formation of Carbocation is Tertiary>Secondary>Primary.

Answer : Option A
Explaination / Solution:

The outcome of oxidation reactions of alcohols depends on the substituents on the carbinol carbon. In order for each oxidation step to occur, there must be H on the carbinol carbon.

• Primary alcohols can be oxidised to aldehydes or further to carboxylic acids. In aqueous media, the carboxylic acid is usually the major product. PCC or PDC, which are used in dichloromethane, allow the oxidation to be stopped at the intermediate aldehyde.
• Secondary alcohols can be oxidised to ketones but no further:
• Tertiary alcohols cannot be oxidised (no carbinol C-H)

Answer : Option A
Explaination / Solution:

Phenol reacts with sodium hydroxide solution to give a colourless solution containing sodium phenoxide. In this reaction, the hydrogen ion has been removed by the strongly basic hydroxide ion in the sodium hydroxide solution.

Answer : Option B
Explaination / Solution:

Phenols are bronsted acids (proton donor). –OH is polar.

Answer : Option A
Explaination / Solution:

Williamson’s synthesis: When an alkyl halide reacts with sodium alkoxide, ether is formed. This reaction is known as Williamson’s synthesis. The reaction generally follows S_N² mechanism for primary alcohols.

Answer : Option D
Explaination / Solution:

Lucas Test is a test which is used to distinguish between primary, secondary and tertiary alcohols. This test is carried out with the help of Lucas reagent, which is a solution of anhydrous Zinc Chloride and concentrated hydrochloric acid (ZnCl₂ + HCl). It is based on the difference between the reactivity of primary, secondary and tertiary alcohols with hydrogen halides.

Answer : Option A
Explaination / Solution:

When –CH₂OH group is replaced by –COOH group then only molecular wt will increase by 14units.

Answer : Option D
Explaination / Solution:

Phenols are more acidic than alcohols Also in phenols if –M groups like –NO₂ are arranged then acidity increases. And –M operates only at o/p position. At m only –I operates.

Answer : Option D
Explaination / Solution:

The functional group of the alcohols is the hydroxyl group, –OH. Unlike the alkyl halides, this group has two reactive covalent bonds, the C–O bond and the O–H bond. The electronegativity of oxygen is substantially greater than that of carbon and hydrogen. Consequently, the covalent bonds of this functional group are polarized so that oxygen is electron rich and both carbon and hydrogen are electrophilic.

Answer : Option C
Explaination / Solution:

Secondary alcohol on oxidation forms ketone which reacts with hydrazine bus doesnot gives silver mirror test.