NEET 2025 · ChemistryPrevious Year Question

The correct order of decreasing acidity of the following aliphatic acids is:

Answer: (A) $HCOOH$ > $CH X_{3} COOH$ > $(CH X_{3}) X_{2} CHCOOH$ > $(CH X_{3}) X_{3} CCOOH$ . \textbf{Answer:} (a) \textbf{Solution:} Acidity is governed by the electron-donating $+ I$ inductive effect of alkyl groups.

A. $HCOOH$ > $CH X_{3} COOH$ > $(CH X_{3}) X_{2} CHCOOH$ > $(CH X_{3}) X_{3} CCOOH$ ✓
B. $HCOOH$ > $(CH X_{3}) X_{3} CCOOH$ > $(CH X_{3}) X_{2} CHCOOH$ > $CH X_{3} COOH$
C. $(CH X_{3}) X_{3} CCOOH$ > $(CH X_{3}) X_{2} CHCOOH$ > $CH X_{3} COOH$ > $HCOOH$
D. $CH X_{3} COOH$ > $(CH X_{3}) X_{2} CHCOOH$ > $(CH X_{3}) X_{3} CCOOH$ > $HCOOH$

Correct Answer

(A) $HCOOH$ > $CH X_{3} COOH$ > $(CH X_{3}) X_{2} CHCOOH$ > $(CH X_{3}) X_{3} CCOOH$

Solution & Explanation

\textbf{Answer:} (a) \textbf{Solution:} Acidity is governed by the electron-donating $+ I$ inductive effect of alkyl groups. More or larger alkyl groups push electron density toward $- COOH$ , destabilising the carboxylate anion and lowering acidity. Formic acid $HCOOH$ has no alkyl group and is strongest; acidity then falls as the $+ I$ effect increases: $HCOOH$ > $CH X_{3} COOH$ (one $CH X_{3}$ ) > $(CH X_{3}) X_{2} CHCOOH$ > $(CH X_{3}) X_{3} CCOOH$ (three $CH X_{3}$ , weakest).

🎯

43,000+ questions in हिंदी & English · one-tap toggle

Practice NEET 2025 Chemistry — free, with instant solutions

The app builds a daily goal from your weak topics and brings each question back just before you forget it — so what you solve today turns into marks on exam day.

Open →📚Practice all NEET Chemistry PYQs chapter-wise →💡Don't get it? Learn the General Principles Of Organic Chemistry concepts →

Chemistry Q2 →

More NEET PYQ solutions

ChemIdentify the suitable reagent for the following conversion: C6H5COOCH3 -> C6H5CHO (methyl benzoate to benzaldehyde)ChemThe correct order of decreasing acidity of the following aliphatic acids is ChemThe major product of the following reaction is: 4-oxo-4-phenylbutanenitrile C6H5-CO-CH2-CH2-CN is treated with (i) CH3MgBr (excess) and then (ii) H3O+.ChemOut of the following complex compounds, which compound will have the minimum conductance in solution?ChemWhich of the following are paramagnetic? A. [NiCl4]^2- B. Ni(CO)4 C. [Ni(CN)4]^2- D. [Ni(H2O)6]^2+ E. Ni(PPh3)4 ChemThe correct order of the wavelength of light absorbed by the following complexes is: A. [Co(NH3)6]^3+ B. [Co(CN)6]^3- C. [Cu(H2O)4]^2+ D. [Ti(H2O)6]^3+ChemThe correct order of decreasing basic strength of the given amines is: (N-ethylethanamine = (C2H5)2NH; ethanamine = C2H5NH2; N-methylaniline = C6H5NH(CH3); benzenamine/aniline = C6H5NH2)ChemPredict the major product P in the following sequence of reactions. The starting material is 1-methylcyclopent-1-ene: (i) HBr, benzoyl peroxide; (ii) KCN; (iii) Na(Hg)/C2H5OH P (major). The structures of the options (A)-(D) are shown in the image below:

More: All NEET 2025 Chemistry PYQs · NEET Chemistry PYQs · All NEET PYQs · Previous year papers