Solution:
The reaction intermediate formed during the preparation of diethyl ether from ethanol by treatment with H2SO4 is carbocation.

Solution:
Biodegradable waste can be found in municipal solid waste (sometimes called biodegradable municipal waste, or as green waste, food waste, paper waste and biodegradable plastics). Other biodegradable wastes include human waste, manure, sewage, sewage sludge and slaughterhouse waste.

Solution:
Bone ash is a white material produced by the calcination of bones. It is primarily composed of calcium phosphate. It is commonly used in fertilizers, polishing compounds and in making ceramics such as bone china. It also has historical uses in the manufacture of baking powders and assay cupels.

Solution:
Covalency of an atom in a covalent compound is the number of covalent bonds formed by an atom. Maximum covalency of Nitrogen is 4 (example - ammonium ions).

Solution:
When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that of valence electron but the mobility is the same. Even for the same electric field, valence electrons cannot move as freely as the free electrons because its movement is restricted due to collisions. Therefore, the velocity of valence electrons is less compared to free electrons. In other words, the velocity of holes is less compared to free electrons. This means mobility is also less for a hole compared to free electron.

Solution:
The chemical name of 'laughing gas' is nitrous oxide.

Solution:
UV photoelectron spectroscopy can provide information on the energy difference between the initial and final states rather the energy levels involved in the transition.