Q3 of 28 Page 187

Why does the colour of copper sulphate change when an iron nail is kept in it? Justify your answer.

According to principle a more reactive element can displace a less reactive element from it’s compound. Iron is more reactive than copper hence when we place iron nails in a solution of copper sulphate the blue colour of the copper sulphate solution changes to green colour and the portion of the iron nail which was dip in the solution acquires a brown colour. This is because iron being more reactive than copper displaces copper from the copper sulphate solution and form ferrous sulphate and the displaced copper gets deposited on the portion of the nail which is dipped in the solution giving a brown colour. The following reaction takes place : -

CuSO4 + Fe → FeSO4 + Cu


More from this chapter

All 28 →
1

What type of chemical reaction takes place when i) limestone is heated?

ii) a magnesium ribbon is burnt in air?

 2

The pH values of certain familiar substances are given below:


Analyse the data in the table and answer the following questions:


i) Which substances are acidic in nature?


ii) Which substances are basic in nature?

 4

The hydroxide ion concentration of a solution is 1.0 x 10 –8M. What is the pH of the solution?

 5

Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid is added to test tube A, while acetic acid is added to test tube B. The amount and concentration taken for both the acids are same. In which test tube does the reaction occur more vigourously and why?