A toxic compound “A” when reacted with NaCN in aqueous acidic medium yields an edible cooking component and food preservative “B”. “B” is converted to “C” by diborane and can be used as an additive to petrol to reduce emission. “C” upon reaction with oleum at 140^circmathrmC$140^{\circ}\mathrm{C}$ yields an inhalable anesthetic “D”. Identify “A”, “B”, “C” and “D”, respectively.

### Core Logic Let's track the conversions row by row based on the description: 1. Toxic compound **A** is methanol (CH_3OH$CH_3OH$). Reacting it via acidic NaCN sequences effectively converts it eventually into acetic acid (CH_3COOH$CH_3COOH$), which is an edible cooking component and food preservative (vinegar) **B**. 2. Reduction of acetic acid (**B**) with diborane (B_2H_6$B_2H_6$) yields ethanol (CH_3CH_2OH$CH_3CH_2OH$) **C**. Ethanol is used as a biofuel additive in petrol. 3. Ethanol (**C**) upon heating with oleum/concentrated sulfuric acid at 140^circmathrmC$140^{\circ}\mathrm{C}$ undergoes intermolecular dehydration to yield diethyl ether (C_2H_5-O-C_2H_5$C_2H_5-O-C_2H_5$) **D**, which functions as an inhalable anesthetic. ### Step 1: Chemical Reaction Sequence Flow

The full sequential progression corresponds exactly to: textMethanol (A) rightarrow textAcetic Acid (B) rightarrow textEthanol (C) rightarrow textDiethyl ether (D)$$\text{Methanol (A)} \rightarrow \text{Acetic Acid (B)} \rightarrow \text{Ethanol (C)} \rightarrow \text{Diethyl ether (D)}$$ ### Pattern Recognition Key temperature indicator: Dehydration of ethanol at 140^circmathrmC$140^{\circ}\mathrm{C}$ yields diethyl ether (ether synthesis), whereas 170^circmathrmC$170^{\circ}\mathrm{C}$ yields ethene gas. Combined with the food preservative clue (acetic acid), the sequence locks instantly to option (3). ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Alcohols, Phenols and Ethers