A toxic compound " A " when reacted with NaCN in aqueous acidic medium yields an edible cooking component…
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 $140^{\circ} \mathrm{C}$ yields an inhalable anesthetic "D". Identify "A", "B", "C" and "D", respectively.