Question

Write one significant observation for each of the following:

(i) Action of heat on ammonium chloride.

(ii) Action of dilute sulphuric acid on zinc carbonate.

(iii) Copper oxide is reduced by hydrogen.

(iv) Anhydrous calcium chloride is exposed to air for sometime.

(v) Sodium carbonate solution is added to calcium chloride solution.​

Answer 1

1. There is liberation of a gas with pungent smell that turns red litmus blue

2. there will be liberation of carbon dioxide which is a combustible gas and colorless and odorless in nature

3. Reddish brown metal of copper will be liberated at

4. there will be change in colour of calcium chloride from white to bluish

5. There will be  chalky white crystal due to formation of the  calcium carbonate crystals

Explanation:

• chemical reaction is a type of reaction when there is change in the chemical bond which are present in the compound.
• The original substance cannot be changed by changing the physical properties of the medium. In addition to this there is a change in colour and the  chemical characteristics which helps in the identification of the type of material which is formed