When a crystal of potassium peramagnate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of pottassium permanganate and water?

When a crystal of copper sulphate is placed at the bottom of a beaker containing water, the water slowly turns blue. Why ?

The pH of a river water sample as measured by pH paper is found to be 6. What does it tell us about water ?

Archit dropped a crystal of potassium permanganate into two beakers A and B containing hot water and cold water respectively. After keeping the beakers undisturbed for some time what did he observe and why ?

Even two or three crystals of potassium permanganate can impart colour to a very large volume of water. Which characteristic of particles of matter is illustrated by this observation ?

All the gases form cathode rays and anode rays when electricity is passed through them : (i) What does the formation of cathode rats tell us about the atoms ? (ii) What des the formation of anode rays tell us about the atoms ?

(a). What happens when zinc granules are heated with sodium hydroxide solution? Write equation of the reaction which takes place. (b). What happens when bases react with non-metal oxides? Explain with the help of an example. What does this reaction tell us about the natrue of non-metal oxides?

Name the process associated with the following (a) Dry ice is kept at room temperature and at one atmospheric pressure. (b) A drop of link placed on the surface of water contained in a glass spreads throughout the water. (c) A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring. (d) A acetone bottle is left open and the bottle becomes empty. (e) Milk is churned to separate cream from it. (f) Settling of sand when a mixture of sand and water is left undisturbed for some time. (g) Fine beam of light entering through a small hole in a dark room. Illuminates the particles in its paths.