Math the important chemicals given in Column (A) with the chemical formulae given in Column (B).

Name the substance which on treatment with chlorine yields bleaching powder.

Name the sodium compound which is used for softening hard water.

A student dropped few pieces of marble in dilute HCl contained in a test tube. The evolved gas was passed through lime water.

(a) What change would be observed in lime water?

(b) Write balanced chemical equation for the above change.

What is the colour of FeSO₄.7H₂O crystals? How does this colour change upon heating? Give balanced chemical equation for the changes.