"A ray of light incident on a rectangular glass slab immersed in any medium emerges parallel to itself." Draw a labelled ray diagram to justify the statement.

Why should biodegradable and non-biodegradable wastes be discarded in two separate dustbins?

"The chromosomes number of the sexually reproducing parents and their offspring is the same." Justify this statement.

We often observe domestic waste decomposing in the by lanes of residential colonies. Suggest ways to make people realize that the improper disposal of waste is harmful to the environment.

Write the name and the structural formula of the compound formed when ethanol is heated at 443 K with excess of cone. H₂SO_4. State the role of conc. H₂SO₄ in this reaction. Write chemical equation for the reaction.