1.
In the following sequence of reactions:
CH3CH2OH→P/Br2\text{CH}_3\text{CH}_2\text{OH} \xrightarrow{\text{P}/\text{Br}_2} A →Mg/ether\xrightarrow{\text{Mg}/\text{ether}} B →HCHO\xrightarrow{\text{HCHO}} C →H2O\xrightarrow{\text{H}_2\text{O}} D
The compound D is: