Question

Give an example of a chemical reaction for each of the following situations:​

(a) A change in colour is observed.​
(b) A gas is evolved.
(c) Sound is produced.

Answer 1

(a) When Iron nails are put into Copper sulphate solution, Iron sulphate and Copper are formed and colour of solution changes from blue to green.​
$\text{Iron (Fe) +}CuS{O}_4\text{(blue)}\to FeS{O}_4\text{(greenish + Copper (Cu))}$

(b) When acetic acid is added to a solution of sodium hydrogen carbonate gas is evolved in the form of bubbles due to the formation of carbon dioxide.​
$\text{Vinegar (Acetic acid) + Baking soda (Sodium hydrogencarbonate )rightarrow}C{O}_2\text{(gas) + other substances}$

(c) Burning of crackers- It is a chemical reaction in which due to the burning of crackers there is production of light, sound and heat. ​