Which one of the following compounds gives acetone $(CH_3)_2C=O$ as one of the products of its ozonolysis?

The correct order of reactivity of hydrogen halides with propene is

Predict the major product of the reaction.

Addition of $HCl$ to $3,3$-dimethyl-$1$-butene yields two products,one of which has a rearranged carbon skeleton. Among the following carbocations,select the possible intermediates in that reaction:
$1.$ $(CH_3)_3C-C^+H-CH_3$
$2.$ $(CH_3)_3C-CH_2-C^+H_2$
$3.$ $(CH_3)_2C(Cl)-C^+(CH_3)_2$
$4.$ $(CH_3)_2C^+-CH(CH_3)_2$

Identify $X$ in the following reaction sequence: Cyclopentane $\xrightarrow{Cl_2/hv} A$ $\xrightarrow{alc. KOH} B$ $\xrightarrow{O_3, Zn/H_2O} X$

$R_f$ value for $2$-methylpropene in a solvent system (Ethyl acetate + ether) is $0.42$. $2$-methylpropene is treated with dilute $H_2SO_4$ to give major organic product $(X)$. $R_f$ value for $(X)$ in the same solvent system under identical condition will be: