### Core Logic Statement (I): The -NH_2$-NH_2$ group has a lone pair of electrons on nitrogen, which undergoes resonance with the benzene ring (strong +M effect). This strongly activates the ring towards electrophilic substitution and directs incoming electrophiles to the ortho and para positions. Statement (II): Friedel-Crafts alkylation and acylation require a Lewis acid catalyst like anhydrous AlCl_3$AlCl_3$. Aniline is a Lewis base (due to the lone pair on N) and reacts with the Lewis acid AlCl_3$AlCl_3$ to form a stable salt/complex (C_6H_5overset+NH_2-AlCl_3^-$C_6H_5\overset{+}{N}H_2-AlCl_3^-$). This removes the lone pair from resonance and converts the -NH_2$-NH_2$ group into a strongly deactivating group, thereby halting the Friedel-Crafts reaction. ### Step 1: Evaluate Statements Statement I is correct. Statement II is correct. ### Pattern Recognition Aniline NEVER undergoes Friedel-Crafts because the base (NH_2$NH_2$) reacts with the catalyst (AlCl_3$AlCl_3$) before the reaction can proceed. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines

### Core Logic Aniline undergoes electrophilic aromatic substitution (like bromination). The -NH_2$-NH_2$ group is a strongly activating group and directs incoming electrophiles to the ortho and para positions due to resonance electron donation (+M$M$ effect). ### Step 1: Identifying Sigma Complexes (Arenium Ions) When an electrophile (Br^+$Br^+$) attacks the ring, an intermediate arenium ion (sigma complex) is formed. - If attack occurs at the **ortho** or **para** position, the positive charge is delocalized onto the carbon atom bearing the -NH_2$-NH_2$ group. The lone pair on nitrogen can then stabilize this positive charge via resonance, forming a highly stable resonance structure (an octet-complete intermediate). - If attack occurs at the **meta** position, the positive charge delocalizes only over the remaining ring carbons and never rests on the carbon bearing the -NH_2$-NH_2$ group. Thus, it misses the extra stabilization provided by the nitrogen lone pair. Because the meta attack intermediate is less stable compared to ortho/para attack, and the -NH_2$-NH_2$ is strictly o/p directing, the meta-arenium ion is NOT a primary intermediate involved in standard bromination pathways of neutral aniline. ### Step 2: Conclusion Option 3 displays the arenium ion resulting from a meta-attack (positive charge skips the -NH_2$-NH_2$ substituted carbon).

Since -NH_2$-NH_2$ is ortho/para directing, the meta-arenium ion will not be formed. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines

### Core Logic Step 1: Bromobenzene + Mg, ether rightarrow Phenylmagnesium bromide$Mg, ether \rightarrow Phenylmagnesium bromide$ (Grignard reagent). Step 2: Grignard + CO_2$CO_2$ followed by H^+ rightarrow Benzoic acid$H^+ \rightarrow Benzoic acid$ (C_6H_5COOH$C_6H_5COOH$). Step 3: Benzoic acid + NH_3, Delta rightarrow Benzamide$NH_3, \Delta \rightarrow Benzamide$ (C_6H_5CONH_2$C_6H_5CONH_2$). Step 4: Benzamide + Br_2/NaOH$Br_2/NaOH$ (Hoffmann bromamide degradation) rightarrow Aniline$\rightarrow Aniline$ (C_6H_5NH_2$C_6H_5NH_2$).

### Step 1: Tracing the product The final product 'A' is Aniline. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines Class 12 Chemistry: Aldehydes, Ketones and Carboxylic Acids Class 12 Chemistry: Haloalkanes and Haloarenes

### Core Logic The reaction sequence represents the classic dye test for aromatic primary amines. Step 1 (Diazotization): Aniline (Ph-NH_2$Ph-NH_2$) reacts with nitrous acid (generated in situ from NaNO_2 + HCl$NaNO_2 + HCl$) at low temperature (0-5^circ C$0-5^\circ C$) to form benzene diazonium chloride (Ph-N_2^+Cl^-$Ph-N_2^+Cl^-$). Thus, Reagent A is NaNO_2 + HCl$NaNO_2 + HCl$ at 0-5^circ C$0-5^\circ C$. ### Step 2: Coupling Reaction Step 2: The diazonium salt undergoes an electrophilic substitution (coupling reaction) with an electron-rich aromatic ring to form an azo dye. The formation of a 'scarlet red dye' is specifically the result of coupling benzene diazonium chloride with beta$\beta$-naphthol in a weakly basic medium (NaOH).

### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines