Activities

Question 1

1.1) When magnesium ribbon is burning, what do you observe?

Answer 1

Magnesium ribbon burns with a dazzling flame and watch powder is collected on the watch glass placed under it. The white powder is magnesium oxide formed by the reaction of magnesium and oxygen present in the air.

2Mg(s) + O2(g) → 2MgO

Question 2

1.2) what do you observe when potassium iodide solution is added to lead nitrate solution in a test tube?

Answer 2

White lead nitrate reacts with white potassium iodide to form yellow lead iodide which is insoluble in water.

Pb(NO3)2(aq) + 2KI(aq) → 2KNO3(aq) + PbI2(s)

Question 3

1.3) What happens to zinc granules when dilute hydrochloric acid is added to it? Is there any change in its temperature?

Answer 3

We can observe bubbles of hydrogen gas being formed around zinc granules. If we touch the conical flask, we can feel a sense of hotness as there is a rise in temperature. So, it’s a exothermic reaction.

Zn + 2HCl → ZnCl2 + H2

Question 4

1.3) What happens to zinc granules when sulphuric acid is added to it? Is there any change in its temperature?

Answer 4

When zinc granules are added to dilute sulphuric acid, there occurs a change in the state of zinc granules and they are converted to zinc sulphate(ZnSO4) and hydrogen gas is evolved.

Zn + H2SO4 → ZnSO4 + H2

This reaction is exothermic, i.e., it involves release of heat and so the flask becomes hot and temperature of the system increases.

Question 5

1.4) Is there any change in temperature when water is added to calcium oxide or quick lime in a beaker?