Which of the following is a natural polymer?

$(a)$ Differentiate between soap and detergent.
$(b)$ Explain why soaps form scum with hard water,whereas detergents do not.

With the help of a diagram,explain the cleansing action of soap.

While cooking,if the bottom of the vessel is getting blackened on the outside,it means that:

An aldehyde as well as a ketone can be represented by the same molecular formula,say $C_{3}H_{6}O$. Write their structures and name them. State the relation between the two in the language of science.

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