Which of the following compounds will give butanone on oxidation with alkaline $KMnO_4$ solution?

The reagent which easily reacts with ethanol and propanol is

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

Consider the following reaction sequence:
$\text{Cyclohexanol}$ $\xrightarrow{CrO_3} A$ $\xrightarrow{CH_3MgBr / H^+, H_2O} B$ $\xrightarrow{H_2SO_4, \Delta} C$ $\xrightarrow{B_2H_6, H_2O_2, OH^-} D$
Identify the final product $D$.

The reaction sequence is as follows:
$2\text{-methylcyclohexanol}$ $\xrightarrow{H^+, \Delta} (A)$ $\xrightarrow{\text{cold dil. } KMnO_4} (B)$ $\xrightarrow{CrO_3} (C)$
Identify the product $(C)$.

Ethylene may be obtained by dehydration of which of the following with concentrated $H_2SO_4$ at $160-170 \ ^oC$?