Which one is an unsaturated compound?

What is the product obtained when the ozonolysis of $CH_2 = CH_2$ is followed by reduction with $LiAlH_4$?

Identify product $C$ in the following reaction: Propylene dibromide $\xrightarrow[\text{Alcohol}]{Zn, \Delta} A$ $\xrightarrow{HBr} B$ $\xrightarrow{Na, \text{ether}} C$

${\text{Glycerol}}$ $\xrightarrow{KHSO_4} (A)$ $\xrightarrow{LiAlH_4} (B)$; $(A)$ and $(B)$ are respectively:

Propene on hydroboration followed by oxidation with alkaline peroxide forms.

Compound$(s)$ that on hydrogenation produce$(s)$ optically inactive compound$(s)$ is (are)