The major product of the following reaction is:

### Related Formula mutextnet = sqrtmu_1^2 + mu_2^2 + 2mu_1mu_2costheta $$\mu{\text{net}} = \sqrt{\mu_1^2 + \mu_2^2 + 2\mu_1\mu_2\cos\theta} $$ textBoiling point propto textDipole-dipole interactions + textVan der Waals forces$$\text{Boiling point} \propto \text{Dipole-dipole interactions} + \text{Van der Waals forces}$$ ### Core Logic Let's analyze the visual structures alongside their scientific orientations: - Statement (I) compares 1,2-dichlorobenzene and 1,2-dibromobenzene. Chlorine has a higher electronegativity than bromine, creating a larger bond dipole. The vacant d-orbital interactions do not invert this baseline dipole trend. Thus, 1,2-dichlorobenzene is more polar, making Statement I correct. - Statement (II) evaluates dihalobenzene isomers. For the para-isomer, individual bond dipoles are oriented at 180^circ$180^{\circ}$, cancelling out completely: mutextpara = 0 $$\mu{\text{para}} = 0 $$ Since mu_textmeta > 0$\mu_{\text{meta}} > 0$, the para-isomer is *less* polar than the meta-isomer. This directly falsifies Statement II. ### Step 1: Spatial Alignments The geometric configurations map out as follows:

Hence, Statement I is correct, but Statement II is incorrect. ### Pattern Recognition Dipole tracking rule: Para-substituted benzenes with identical groups possess a structural center of inversion, guaranteeing a net dipole moment of exactly zero (mu = 0$\mu = 0$). They can never be more polar than any asymmetric ortho or meta structural isomer. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Haloalkanes and Haloarenes

### Core Logic The substrate contains two distinct carbon-halogen bonds: an aryl-bromide bond (mathrmAr-Br$\mathrm{Ar-Br}$) on the ring and an aliphatic alkyl-chloride bond (mathrmCH_2-Cl$\mathrm{CH_2-Cl}$) on the side chain. 1. **Aryl Halide Site (mathrmC_sp^2mathrm-Br$\mathrm{C}_{sp^2}\mathrm{-Br}$):** The bromine atom attached directly to the aromatic ring does not undergo standard nucleophilic substitution (S_N2$S_N2$ or S_N1$S_N1$) under normal conditions due to resonance stabilization, which gives the bond partial double-bond character. 2. **Alkyl Halide Site (mathrmC_sp^3mathrm-Cl$\mathrm{C}_{sp^3}\mathrm{-Cl}$):** The side-chain aliphatic carbon bond undergoes smooth, unhindered nucleophilic substitution. When reacting with silver cyanide (mathrmAgCN$\mathrm{AgCN}$): mathrmAgCN$\mathrm{AgCN}$ is predominantly covalent. The lone pair on the nitrogen atom acts as the primary nucleophilic center rather than the carbon atom. Consequently, substitution at the aliphatic site yields an **isonitrile (-mathrmNC$-\mathrm{NC}$)** derivative as the major product, leaving the aryl bromide group completely untouched. ### Step 1: Structural Resolution The reaction progresses cleanly at the side-chain carbon:

### Pattern Recognition Remember the key selectivity rule for cyanide nucleophiles: * mathrmKCN / mathrmNaCN ightarrow$\mathrm{KCN} / \mathrm{NaCN} ightarrow$ ionic reagents ightarrow$ ightarrow$ attacks via carbon to form a **Nitrile (-mathrmCN$-\mathrm{CN}$)**. * mathrmAgCN ightarrow$\mathrm{AgCN} ightarrow$ covalent reagent ightarrow$ ightarrow$ attacks via nitrogen to form an **Isonitrile (-mathrmNC$-\mathrm{NC}$)**. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Haloalkanes and Haloarenes

### Core Logic Analyzing the solvent effects on reaction kinetics: - In Statement-I, the reaction involves an anionic nucleophile (OH^-$OH^{-}$), creating a highly localized charge density on the reactant side. The resulting transition state disperses this negative charge over a larger volume, lowering its charge density. Highly polar solvents strongly solvate the reactant ion, increasing the activation energy barrier. Consequently, less polar solvents accelerate this process.

- In Statement-II, the reaction begins with neutral precursors (R_3N$R_3N$ and alkyl chloride). The resulting transition state develops partial charges (delta+$\delta+$ and delta-$\delta-$) as the new bond forms, increasing its charge density relative to the reactants. Polar solvents stabilize this charged transition state, lowering the activation energy barrier. Thus, highly polar media accelerate this substitution pathway.

### Pattern Recognition If the transition state concentrates charge relative to the reactants, polar solvents accelerate the reaction. If the transition state disperses charge, less polar solvents are favored. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Haloalkanes and Haloarenes

### Related Formula Markovnikov addition of HCl$HCl$ across an alkene: R-CH=CH_2 + HCl rightarrow R-CHCl-CH_3$$R-CH=CH_2 + HCl \rightarrow R-CHCl-CH_3$$ Nucleophilic substitution with AgCN$AgCN$ favors coordinate carbon bonding over nitrogen, yielding covalent isocyanides (R-NC$R-NC$). ### Core Logic Step 1: The starting material contains a double bond. Treating it with HCl$HCl$ leads to addition. According to Markovnikov's rule, the chloride ion attaches to the secondary position, creating chloride intermediate [A]$[A]$. Step 2: Compound [A]$[A]$ reacts with AgCN$AgCN$. Since AgCN$AgCN$ is covalent, the lone pair on nitrogen acts as the attacking nucleophile, leading to substitution with an isocyanide group (-NC$-NC$) rather than a cyanide group (-CN$-CN$). ### Step 1: Structural Synthesis The intermediate [A]$[A]$ possesses a chlorine atom at the secondary carbon position. Substituting this chlorine with -NC$-NC$ provides the product corresponding to option (4).

### Pattern Recognition Distinguish between ionic vs covalent cyanide sources: - KCN / NaCN implies$KCN / NaCN \implies$ forms alkyl nitriles (R-CN$R-CN$) - AgCN implies$AgCN \implies$ forms alkyl isocyanides (R-NC$R-NC$) ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Haloalkanes and Haloarenes