Question

6. Explain why:
(i) Ferric chloride is stored in air-tight bottles.
On exposure to air, Glauber's salt loses weight while quicklime gains weight.
Common salt (containing traces of magnesium chloride) becomes sticky during the monsoons.
(iv) Blue copper sulphate crystals turn white on heating.
(v) Anhydrous calcium chloride is used in desiccators.
(vi) Conc. sulphuric acid becomes dilute when exposed to air.
(vii) Universal indicator is preferred to acid-base indicators.​

Answer 1

Answer:

Explanation:

1. Ferric chloride is highly deliquescent in nature. When exposed to atmosphere it absorbs moisture and gets converted into its saturated solution, therefore it should be stored in airtight bottles.
3. Common salt become sticky during rainy season because During this season the air in the surroundings and in the atmosphere becomes humid and when this water in the atmosphere( Humidity In the Air) comes in contact with the salt particles, the salt becomes sticky
4. The blue coloured copper sulphate crystals turns white due to the loss of water molecules. The formula of copper sulphate is CuSO4. 5H2O. When copper sulphate is heated, it looses water molecules and hence it looses blue colour.
5. The purpose of using desiccators is to absorb moisture. Anhydrous Calcium chloride (CaCl2) has a capacity of absorbing moisture as it is hygroscopic in nature, so it is used as a desiccators.
6. conc. sulphuric acid becomes dilute when exposed to air ?? Concentrated sulphuric acid become dilute when exposed to air due to its strong dehydrating property. This dehydrating property of sulphuric acid acid allow it absorb moisture from environment and it tends to become dilute.
7. The advantage of the universal indicator is that it displays a variety of colors over the whole pH scale. This makes it possible to determine an approximate pH of a solution over a range from 1-14. whereas, A commonly used acid-base indicator is litmus.