The correct order of acidic strength of the major products formed in the given reactions, is:

Choose the correct answer from the options given below:

### Core Logic Identify the major products [A], [B], [C], and [D]: (A) PhNH_2 xrightarrow1) NaNO_2 + HCl PhN_2^+Cl^- xrightarrow2) CuCN PhCN xrightarrow3) H_3O^+ PhCOOH$PhNH_2 \xrightarrow{1) NaNO_2 + HCl} PhN_2^+Cl^- \xrightarrow{2) CuCN} PhCN \xrightarrow{3) H_3O^+} PhCOOH$ (Benzoic acid) (B) CH_3CH_2CHO xrightarrow[Ag(NH_3)_2]^+, OH^- CH_3CH_2COOH$CH_3CH_2CHO \xrightarrow{[Ag(NH_3)_2]^+, OH^-} CH_3CH_2COOH$ (Propanoic acid) (C) CH_4 + O_2 xrightarrowMo_2O_3 HCHO xrightarrowNa_2Cr_2O_7/H^+ HCOOH$CH_4 + O_2 \xrightarrow{Mo_2O_3} HCHO \xrightarrow{Na_2Cr_2O_7/H^+} HCOOH$ (Formic acid) (D) PhCH_2MgBr + CO_2 xrightarrowH_3O^+ PhCH_2COOH$PhCH_2MgBr + CO_2 \xrightarrow{H_3O^+} PhCH_2COOH$ (Phenylacetic acid) ### Step 1: Compare Acidity

Acidity order: Formic acid > Benzoic acid > Phenylacetic acid > Propanoic acid. HCOOH$HCOOH$ (C) has no +I alkyl group, making it the strongest. PhCOOH$PhCOOH$ (A) has an sp^2$sp^2$ carbon attached directly, which is mildly electron withdrawing via -I relative to alkyls. PhCH_2COOH$PhCH_2COOH$ (D) has an sp^3$sp^3$ methylene spacer, so -I from phenyl is weakened. CH_3CH_2COOH$CH_3CH_2COOH$ (B) has a purely electron-donating ethyl group (+I effect), making it the weakest. ### Step 2: Final Conclusion Order is C > A > D > B$C > A > D > B$. ### Pattern Recognition HCOOH$HCOOH$ is stronger than PhCOOH$PhCOOH$. Aliphatic acids with +I groups are the weakest. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Carboxylic Acids Class 12 Chemistry: Amines Class 12 Chemistry: Aldehydes, Ketones and Carboxylic Acids