The functional group that can be identified through phthalein dye test is:

Q: The functional group that can be identified through phthalein dye test is:

Phthalein dye test is specific for phenolic -OH groups. Phenol condenses with phthalic anhydride in presence of conc. H2SO4 to form phenolphthalein, giving pink colour in alkali. Functional group identified is Phenolic. Phthalein dye test arrow Specific qualitative test for Phenols. Class 12 Chemistry: Alcohols, Phenols and Ethers

Year	2024	Total
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Solution & Explanation

Related Formula

Phenol + Phthalic anhydride conc. H₂SO₄ Phenolphthalein NaOH Pink colour

Core Logic

Phthalein dye test is specific for phenolic $-OH$ $-OH$ groups. Phenol condenses with phthalic anhydride in presence of conc. $H₂SO₄$ $H_2SO_4$ to form phenolphthalein, giving pink colour in alkali.

Step 1: Conclusion

Functional group identified is Phenolic.

Pattern Recognition

Phthalein dye test $arrow$ $\rightarrow$ Specific qualitative test for Phenols.

Chapter Mix

Class 12 Chemistry: Alcohols, Phenols and Ethers

More Alcohols, Phenols and Ethers Previous-Year Questions

Q46 neet_2024_05_may_morning Chemical Reactions and Conversions

Match List I with List II

List-I	List-II
A. $H₃C-CH(OH)-CH₃$ $H_3C-CH(OH)-CH_3$	(I) (i) Oleum; (ii) $NaOH, Δ$ $NaOH, \Delta$; (iii) $H^+$ $H^+$
B. $CH₃COOH arrow CH₃CH₂OH$ $CH_3COOH \rightarrow CH_3CH_2OH$	(II) (i) $O₂$ $O_2$; (ii) $H₂O/H^+$ $H_2O/H^+$
C. $CH₃CH₂CH₂OH arrow CH₃CH(OH)CH₃$	(III) (i) $CH₃OH, H^+$ $CH_3OH, H^+$; (ii) $H₂$ $H_2$, catalyst
D. Cumene to Phenol	(IV) (i) conc. $H₂SO₄, Δ$ $H_2SO_4, \Delta$; (ii) $H^+/H₂O$ $H^+/H_2O$

Choose the correct answer from the options given below:

Chemical Reactions diagram for Q46 - JEE Main 2026 Morning — Reagent mapping for functional group conversions in organic chemistry.

A. (1) A-I, B-III, C-IV, D-II
B. (2) A-II, B-IV, C-III, D-I
C. (3) A-II, B-III, C-I, D-IV
D. (4) A-II, B-III, C-IV, D-II

Solution

Related Formula

Cumene + O₂ arrow Cumene hydroperoxide H^+/H₂O Phenol + Acetone

Core Logic

A. Cumene hydroperoxide process gives Isopropanol/Phenol conversions (II).

B. Reduction of carboxylic acid via esterification followed by catalytic reduction (III).

C. Dehydration followed by hydration (IV).

D. Phenol synthesis from benzene via oleum/sulfonation (I).

Step 1: Conversion Breakdown

Matching each reaction pair gives A-II, B-III, C-IV, D-I.

Pattern Recognition

Identify key named reactions: Cumene oxidation gives phenol + acetone; Acid reduction requires esterification intermediate.

Chapter Mix

Class 12 Chemistry: Alcohols, Phenols and Ethers

Q52 neet_2024_05_may_morning Reaction Sequences of Alcohols

In the following reaction sequence, X and Z respectively are:

Reaction sequence diagram for Q52 - JEE Main 2026 Morning — Multistep reaction sequence starting from propan-1-ol with PCl5 and peroxide addition.

A. (1) $X = POCl₃; Z = CH₃-CH(Br)-CH₃$ $X = POCl_3; Z = CH_3-CH(Br)-CH_3$
B. (2) $X = H₃PO₃; Z = CH₃CH₂CH₂-Br$ $X = H_3PO_3; Z = CH_3CH_2CH_2-Br$
C. (3) $X = H₃PO₃; Z = CH₃-CH(Br)-CH₃$ $X = H_3PO_3; Z = CH_3-CH(Br)-CH_3$
D. (4) $X = POCl₃; Z = CH₃CH₂CH₂-Br$ $X = POCl_3; Z = CH_3CH_2CH_2-Br$

Solution

Related Formula

R-OH + PCl₅ arrow R-Cl + POCl₃ + HCl

CH₃-CH=CH₂ + HBr Peroxide CH₃CH₂CH₂Br

Core Logic

Propan-1-ol + $PCl₅ arrow CH₃CH₂CH₂Cl + POCl₃ + HCl X = POCl₃$ .
Dehydrohalogenation with alc. $KOH$ $KOH$ yields propene ( $Y = CH₃CH=CH₂$ $Y = CH_3CH=CH_2$).
Anti-Markovnikov addition of $HBr$ $HBr$ in presence of peroxide $(CH₃COO)₂$ $(CH_3COO)_2$ yields 1-bromopropane ( $Z = CH₃CH₂CH₂Br$ $Z = CH_3CH_2CH_2Br$).

Step 1: Final Identification

$X = POCl₃$ $X = POCl_3$ and $Z = CH₃CH₂CH₂Br$ $Z = CH_3CH_2CH_2Br$.

Pattern Recognition

$PCl₅$ $PCl_5$ gives $POCl₃$ $POCl_3$ side product (whereas $PCl₃$ $PCl_3$ gives $H₃PO₃$ $H_3PO_3$). Peroxide + $HBr$ $HBr$ guarantees terminal addition.

Chapter Mix

Class 12 Chemistry: Alcohols, Phenols and Ethers

The functional group that can be identified through phthalein dye test is:

Solution & Explanation

Related Formula

Core Logic

Step 1: Conclusion

Pattern Recognition

Chapter Mix

Reference Study Guides

More Alcohols, Phenols and Ethers Previous-Year Questions

Solution

Related Formula

Core Logic

Step 1: Conversion Breakdown

Pattern Recognition

Chapter Mix

Solution

Related Formula

Core Logic

Step 1: Final Identification

Pattern Recognition

Chapter Mix

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The functional group that can be identified through phthalein dye test is:

Solution & Explanation

Related Formula

Core Logic

Step 1: Conclusion

Pattern Recognition

Chapter Mix

Reference Study Guides

More Alcohols, Phenols and Ethers Previous-Year Questions

Solution

Related Formula

Core Logic

Step 1: Conversion Breakdown

Pattern Recognition

Chapter Mix

Solution

Related Formula

Core Logic

Step 1: Final Identification

Pattern Recognition

Chapter Mix

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