The adduct of the compound $'A'$ obtained by the reaction with excess of isopropyl magnesium iodide,upon hydrolysis gives a tertiary alcohol. The compound $'A'$ is

$A$ compound with formula $C_4H_{10}O$ on oxidation gives $C_4H_8O$,which forms an oxime and gives a positive iodoform test. The original compound on reaction with concentrated $H_2SO_4$ gives $C_4H_8$. What is the structure of the compound?

Iodoform can be prepared from all,except

Which of the following is a secondary benzylic alcohol?

$X + HCl$ $\xrightarrow[\text{Addition}]{\text{Anhy. } AlCl_3} C_2H_5Cl \xleftarrow[\text{Substitution}]{\text{Anhy. } ZnCl_2/HCl} Y$. The conversion of $Y$ to $X$ can be achieved by heating with .......... at .......... temperature.

Main constituent of dynamite is