Question

State one characteristic each of chemical reactions which take place when:

a) dilute hydrochloric acid is added to sodium carbonate

b)lemon juice is added gradually to potassium permanganate solution

c) dilute sulphuric acid is added to barium chloride solution

d) quicklime is treated with water

Answer 1

1) Na2CO3 + 2 HCl --------> 2 NaCl + CO2 + H2O

2) Lemon juice converts purple colour of the potassium permanganate to colorless as it is acidic.

3) BaCl2 + H2SO4 --------> BaSO4 + 2HCl

4) CaO (s) + H2O (l)Ca(OH)2

Answer 2

(a)CO2 gas is released whose presence can be tested by lime water test.
(b)purple colour of potassium permanganate changes to colourless or very faint pink.
(c)an insoluble white ppt of baso4 is formed
(d)a large amount of heat is released because it is a highly exothermic reacn