JEE Mains · Chemistry · STD 12 - 7. Alcohol, phenol and ethers

Consider compounds A, B and C with following structural formulae
\(A = \) CH\(_3\) - CH\(_2\) - CH\(_2\) - CH\(_2\) - CH\(_2\) - OH
\(B = \) CH\(_2 =\) CH - CH\(_2\) - CH\(_2\) - CH\(_3\)
\(C = \) HO - CH\(_2\) - CH\(_2\) - CH(OH) - CH\(_3\)
For the conversion of B from A, reagent (D) required is _ and structural formula of product (E) obtained when C undergoes same reaction using excess reagent (D) is _.

A
D E
Conc. H\(_2\)SO\(_4\) CH\(_2 =\) CH \(-\) CH(OH)CH\(_3\)
B
D E
PCC HO \(-\) CH\(_2\) \(-\) CH\(_2\) \(-\) CH \(=\) CH\(_2\)
C
D E
PCC CH\(_2 =\) CH \(-\) CH \(=\) CH\(_2\)
D
D E
Conc. H\(_2\)SO\(_4\) or H\(_3\)PO\(_4\) CH\(_2 =\) CH \(-\) CH \(=\) CH\(_2\)

Verified Solution

Answer & Solution

Correct Answer

(D)

D	E
Conc. H\(_2\)SO\(_4\) or H\(_3\)PO\(_4\)	CH\(_2 =\) CH \(-\) CH \(=\) CH\(_2\)

Step-by-step Solution

Detailed explanation

Compound A is pentan-1-ol (\(CH_3-CH_2-CH_2-CH_2-CH_2-OH\)) and Compound B is pent-1-ene (\(CH_2=CH-CH_2-CH_2-CH_3\)). The conversion of an alcohol to an alkene is a dehydration reaction, which requires an acidic dehydrating agent such as concentrated \(H_2SO_4\) or \(H_3PO_4\).…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match List \(I\) with List \(II\)

List \(I\) (Natural amino acid) List \(II\) (Code)

\(A\) Glutamic acid \(I\) \(Q\)

\(B\) Glutamine \(II\) \(W\)

\(C\) Tyrosine \(III\) \(E\)

\(D\) Tryptophan \(IV\) \(Y\)

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Match \(List-I\) with \(List-II\)

\(List-I\)	\(List-II\)
\(A\) \(Ni ( CO )_{4}\)	\(I\) \(sp ^{3}\)
\(B\) \({\left[ Ni ( CN )_{4}\right]^{2-} }\)	\(II\) \(S p^{3} d^{2}\)
\(C\) \({\left[ Co ( CN )_{6}\right]^{3-} }\)	\(III\) \({d^{2}}\)
\(D\) \({\left[ CoF _{6}\right]^{3-} }\)	\(IV\) \({s p^{3}}{d s p^{2}}\)

Choose the correct answer from the options given below.

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D	E
PCC	HO \(-\) CH\(_2\) \(-\) CH\(_2\) \(-\) CH \(=\) CH\(_2\)

List \(I\) (Natural amino acid)	List \(II\) (Code)
\(A\) Glutamic acid	\(I\) \(Q\)
\(B\) Glutamine	\(II\) \(W\)
\(C\) Tyrosine	\(III\) \(E\)
\(D\) Tryptophan	\(IV\) \(Y\)