Identify the product of ozonolysis of $but-2-ene$ from the following:

Addition of $HBr$ to propene yields $2$-bromopropane,while in the presence of benzoyl peroxide,the same reaction yields $1$-bromopropane. Explain and give mechanism.

In the hydroboration-oxidation reaction of propene with diborane,$H_2O_2$,and $NaOH$,the organic compound formed is:

Propanal and pentan-$3$-one are the ozonolysis products of an alkene. What is the structural formula of the alkene?

In the reaction,$H_2C = CH_2 \xrightarrow{\text{cold alkaline } KMnO_4} (A)$. Product $A$ is :

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