What is the percentage of sulfur used in vulcanized rubber for battery casings (in $\%$)?

What happens when ethyl alcohol and acetic acid react with each other in the presence of conc. $H_{2}SO_{4}$?

What are soaps? Why do they form scum with hard water?

$CH_3-CH_2-OH \xrightarrow{\text{Alkaline } KMnO_4 + \text{Heat}} CH_3-COOH$
In the above given reaction,alkaline $KMnO_4$ acts as:

Identify and name the functional groups present in the following compounds:
$(a)$ $CH_3-CH_2-CH_2-OH$
$(b)$ $CH_3-CH_2-COOH$

What is the role of the metal or reagents written on the arrows in the given chemical reactions?
$(a)$
$(b)$ $CH_{3}COOH + CH_{3}CH_{2}OH \xrightarrow{Conc. H_{2}SO_{4}} CH_{3}COOC_{2}H_{5} + H_{2}O$
$(c)$ $CH_{3}CH_{2}OH \xrightarrow[Heat]{Alkaline KMnO_{4}} CH_{3}COOH$