In the presence of which enzyme does the fermentation of an aqueous solution of sugar or molasses produce glucose and fructose?

Write the name and general formula of a chain of hydrocarbons in which an addition reaction with hydrogen is possible. State the essential condition for an addition reaction. Stating this condition,write a chemical equation giving the name of the reactant and the product of the reaction.

What will you observe on adding a $5\%$ alkaline potassium permanganate solution drop by drop to some warm ethanol taken in a test tube? Write the name of the compound formed during the above chemical reaction.

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

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

Unsaturated hydrocarbons produce a yellow flame with a large amount of black smoke when burnt in oxygen. Give the reason.