Question

State your observation in each of the following cases: 

1. When dilute hydrochloric acid is added to sodium carbonate crystals. 

2. When excess sodium hydroxide is added to calcium nitrate solution. 

3. At the cathode when acidified aqueous copper sulphate solution is electrolyzed with copper electrodes. 

4. When calcium hydroxide is heated with ammonium chloride crystals. 

5. When moist starch iodide paper is introduced into chlorine gas. 

Answer 1

1. Brisk effervescence with the release of a colourless odourless gas that extinguish a glowing splint and turns lime water milky i.e., CO₂ gas is released. 

2. A white ppt of Ca(OH)₂ is obtained that remains insoluble in excess of NaOH. 

3. The blue colour of aq.CuSO₄ remains unchanged. 

4. A colourless pungent smelling basic gas i.e., Ammonia is obtained. 

5. Moist starch iodide paper turns blue black.