In which of the following reactions of alcohol is there no cleavage of the $C-O$ bond?

How many structural isomers of ${C_5}{H_{11}}OH$ are primary alcohols?

The major product of the following reaction is:

The product of the reaction is:

The alcohol that reacts faster with Lucas reagent is

$A$ sample of $4.5 \ g$ of an unknown monohydric alcohol,$ROH$,was added to methylmagnesium iodide. $A$ gas is evolved,collected,and its volume is measured to be $3.1 \ L$ at $NTP$. The molecular weight of the unknown alcohol is $g/mol$. [Nearest integer]