The dehydration of alcohols is an example of ...... .

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$:
Assertion $A$: Alcohols react both as nucleophiles and electrophiles.
Reason $R$: Alcohols react with active metals such as sodium,potassium and aluminum to yield corresponding alkoxides and liberate hydrogen.
In the light of the above statements,choose the correct answer from the options given below:

Compound $(x)$ with molecular formula $C_4H_8O$ gives a positive haloform test but does not give a $2,4-DNP$ test. The compound is:

$A$ better reagent to oxidize primary alcohols into aldehydes is

At room temperature,the alcohol that does not react with Lucas reagent is:

The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with