JEE Main · 2007 · 29 Apr 2007 · Offline · Alcohols Phenols and Ethers

Ethanol treated with red phosphorus and iodine is converted into ethyl iodide, which on reaction with magnesium in dry ether gives the Grignard reagent ethylmagnesium iodide. Adding this reagent to formaldehyde, $\mathrm{HCHO}$, forms a new carbon-carbon bond, and aqueous work-up of the resulting alkoxide gives a primary alcohol one carbon longer than the alkyl group of the reagent. Building on the two-carbon ethyl unit with the formaldehyde carbon yields $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{OH}$, so the final compound is n-propyl alcohol.