Identify the species $X$ in the reaction: $CH_3-CH=CH_2 + [O] \xrightarrow{\text{conc. acidic } KMnO_4} X + HCOOH$

An alkene $A$ on reaction with $O_{3}$ and $Zn-H_{2}O$ gives propanone and ethanal in equimolar ratio. Addition of $HCl$ to alkene $A$ gives $B$ as the major product. The structure of product $B$ is:

The correct statement about $C$ and $D$ is:
$CH_3-C \equiv C-CH_3$ $\xrightarrow{H_2/Pd-BaSO_4} A$ $\xrightarrow{Br_2/CCl_4} C$
$CH_3-C \equiv C-CH_3$ $\xrightarrow{Na/Liq. NH_3} B$ $\xrightarrow{Br_2/H_2O} D$

When glycerol is heated with concentrated sulfuric acid,a compound with a pungent odor is formed. What is this compound?

Identify the product of the following reaction: $CH_3-CH=CH-CH_3 \xrightarrow[(ii) H_2O, Zn]{(i) O_3} \text{Product}$

Write the main product of the given reactions:
$(1)$ $CH_3-CH=C(CH_3)_2 + HCl \to$
$(2)$ $3-\text{Methylbut-}1-\text{ene} + HBr \to$