The major product obtained when ethanol is heated with excess of conc. $H_2SO_4$ at $443 \ K$ is:

In the given pairs of alcohols,in which pair is the second alcohol more reactive than the first towards hydrogen bromide $(HBr)$?

$HO-CH_2-C(=O)-CH(OH)-CH_2-OH \xrightarrow{HIO_4} \text{Product obtained is}$

$CH_3MgBr + \text{Cyclopentanone}$ $\xrightarrow{H_3O^{+}} A$ $\xrightarrow{HBr} B$ $\xrightarrow{Mg/\text{ether}} C$ $\xrightarrow{HCHO}_{H_3O^{+}} D$ $\xrightarrow{HI} E$
$E$ is

Which of the following gives a blue color on reaction with $P + I_2$,followed by $AgNO_2$,$HNO_2$,and finally $NaOH$?

When ethyl alcohol $({C_2}{H_5}OH)$ reacts with thionyl chloride,in the presence of pyridine,the product obtained is