Draw the structure for ethanoic acid molecule, CH₃COOH.

Give an example of a phenomenon where tyndall effect can be observed.

What is meant by biological magnification?

Explain with the help of a diagram, how we are able to observe the sunrise about two minutes before the sun gets above the horizon.

How does the valency of elements very (i) in going down a group, and (ii) in going from left to right in a period of the periodic table?