What is the decreasing order of acidic strength for ethane $(I)$,ethene $(II)$,ethyne $(III)$,and propyne $(IV)$?

Compound $(A)$ is

What are $B$ and $C$ respectively in the following set of reactions?
$C \xleftarrow[\Delta]{Zn} 1,2-\text{dibromopropane}$ $\xrightarrow[\text {(ii) } NaNH_2]{\text {(i) alc. } KOH} A$ $\xrightarrow[\text { Catalyst }]{\text { Lindlar }} B$

For the following compounds,write structural formulas and $IUPAC$ names for all possible isomers having the number of double or triple bonds as indicated:
$(a)$ $C_4H_8$ (one double bond)
$(b)$ $C_5H_8$ (one triple bond)

What is the product of the mild oxidation of glycerol using $H_2O_2/FeSO_4$?

$A$ hydrocarbon with molecular formula $C_4H_6$ undergoes the following reactions:
$A$. Decolourises molecular bromine.
$B$. Reacts with $HBr$.
$C$. Addition of ozone and then cleavage of the ozonide by $Zn / H_2O$ gives the product $C_4H_6O_2$.
Then,the structure of the hydrocarbon is: