List two observation you would record in your notebook 30 minutes after adding iron filling to copper sulphate solution.

Iron nails become _______ after being dipped in copper sulphate solution.

State one observation: A zinc granule is added to copper sulphate solution.

(a) List two observations that are noticed when an iron nail is put inside copper sulphate solution. Write chemical equation for the reaction that occurs. (b) Explain two ways by which rancidity of food materials can be checked.

State any one observation for each of the Ammonium hydroxide solution is added in excess to copper sulphate solution.

• Take three iron nails and clean them by rubbing with sand paper. • Take two test tubes marked as (A) and (B). In each test | tube, take about 10 ml copper sulphate solution. • Tie two iron nails with a thread and immerse them 'carefully in the copper sulphate solution in test tube B for about 20 minutes [Fig. (a)]. Keep one iron nail aside for comparison. • After 20 minutes, take out the iron nails from the copper sulphate solution. • Compare the intensity of the blue colour of copper sulphate solutions in test tubes (A) and (B) (Fig. (b)]. Also, compare the colour of the iron nails dipped in the copper sulphate solution with the one kept aside [Fig. - (b)]. On the basis of activity , give the answers of th following questions : What is the colour of copper sulphat solution in test tube A ?

What changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution for about 30 minutes?

State one observation for the following : A zinc granule is added to copper sulphate solution.