Solution:
The total energy of a revolving electron in any orbit is the sum of its kinetic and potential energies. Energy of an electron at infinite distance from the nucleus is zero. As an electron approaches the nucleus, the electron attraction increases and the energy of electron decreases and thus becomes negative. Thus, it can never be positive.

Solution:
Xenon can form compounds.

Solution:
Typical organic compounds are combustible by nature as they contain carbon. Organic compounds mostly consist of carbon, hydrogen, halogen, and phosphorus.

Solution:
The fermentation of sugar into ethanol is one of the earliest biotechnologies employed by humanity. Fermentation of fermentable sugars by suitable yeast produces ethanol (ethyl alcohol). Yeast is a single celled fungus containing a number of enzymes useful during fermentation. Brewers yeast and wine yeast, for example, contain zymase, an enzyme that can convert glucose to ethanol.

Solution:
Higher concentration of nitrogen dioxide in atmosphere air causes bronchitis.

Solution:
Lactose is a disaccharide sugar composed of galactose and glucose. Lac in Latin means milk. It comprises about 2-8 % of milk by weight so, it is important constituent of milk. It is also called as milk sugar.

Solution:
Commonly used antiseptic, dettol is a mixture of chloroxylenol and terpineol.