Question

Observe the following set of reactions: 

Correct statement regarding Y and B is: 
 

• A. Both Y and B are dehydrated with Conc. H\(_2\)SO\(_4\)/443 K
• B. Both Y and B are dehydrated with 20% H\(_3\)PO\(_4\)/358 K
• C. Y is dehydrated with Conc. H\(_2\)SO\(_4\)/443 K and B with 20% H\(_3\)PO\(_4\)/358 K
• D. B is dehydrated with Conc. H\(_2\)SO\(_4\)/443 K and Y with 20% H\(_3\)PO\(_4\)/358 K

Hint:

Remember the reactions of alkynes and alkenes, and the dehydration conditions for different types of alcohols.

Answer 1

The Correct Option is D

1. Reaction of C\(_3\)H\(_4\) with Hg\(^{2+}\)/H\(_2\)O:

C\(_3\)H\(_4\) is propyne (CH\(\equiv\)C-CH\(_3\)).
Hydration of alkynes in the presence of Hg\(^{2+}\)/H\(_2\)O leads to the formation of a ketone.
X is propanone (CH\(_3\)COCH\(_3\)).

2. Reaction of propanone with MeMgBr followed by H\(_2\)O:

Propanone reacts with methyl magnesium bromide (MeMgBr) to form a tertiary alcohol.
Y is 2-methylpropan-2-ol ((CH\(_3\))\(_3\)COH).

3. Reaction of C\(_3\)H\(_6\) with (BH\(_3\))\(_2\) followed by H\(_2\)O\(_2\)/OH\(^{-}\):

C\(_3\)H\(_6\) is propene (CH\(_3\)CH=CH\(_2\)).
Hydroboration-oxidation of alkenes leads to the formation of an alcohol.
B is propan-1-ol (CH\(_3\)CH\(_2\)CH\(_2\)OH).

4. Dehydration of alcohols:

Tertiary alcohols (Y) are easily dehydrated with mild conditions like 20% H\(_3\)PO\(_4\)/358 K.
Primary alcohols (B) require stronger conditions like Conc. H\(_2\)SO\(_4\)/443 K for dehydration.

Therefore, B is dehydrated with Conc. H\(_2\)SO\(_4\)/443 K and Y with 20% H\(_3\)PO\(_4\)/358 K.

Final Answer:
B is dehydrated with Conc. H\(_2\)SO\(_4\)/443 K and Y with 20% H\(_3\)PO\(_4\)/358 K.