COMEDK · Chemistry · 26. Alcohols Phenols and Ethers

Choose the correct order of increasing acidic strength of the following compounds.

A \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CCl}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CF}_3 \mathrm{CH}_2 \mathrm{OH}\)
B \(\mathrm{CCl}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CF}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}\)
C \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CF}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CCl}_3 \mathrm{CH}_2 \mathrm{OH}\)
D \(\mathrm{CF}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CCl}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}\)

Verified Solution

Answer & Solution

Correct Answer

(A) \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CCl}_3 \mathrm{CH}_2 \mathrm{OH}<\mathrm{CF}_3 \mathrm{CH}_2 \mathrm{OH}\)

Step-by-step Solution

Detailed explanation

The acidic strength of alcohols depends on the stability of the conjugate base (alkoxide ion) formed after the loss of a proton. The stability of the alkoxide ion is increased by the presence of electron-withdrawing groups (EWG) through the inductive effect (-I effect). The…

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

Inductive effect involves

COMEDK 2018 Easy

Match the details given in Column I with those given in Column II

S.No.	Column I	S.No.	Column II
A	For complex reactions order is determined by	P	Rate of reaction.
B	For Zero order reaction unit of k is same as that of	Q	Slope \(= k/2.303\)
C	Mathematical expression which gives relationship between rate of reaction and concentrations of reactants is called	R	Slowest rate determining step.
D	For a first order reaction plot of \(\log[R_0]/[R]\) vs time gives	S	Rate law.

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