Answer: Mining rock salt or evaporation of seawater.
- A Mining rock salt or evaporation of seawater
- B Electrolysis of aqueous NaOH solution in a diaphragm cell
- C The Solvay process used industrially to manufacture sodium carbonate
- D Direct combination of sodium metal with chlorine gas alone
Correct answer: A. Mining rock salt or evaporation of seawater
Explanation: Salt is obtained naturally from rock salt deposits or by evaporation of seawater in salt pans.
Each s-block metal ion emits a characteristic flame colour because heating excites electrons to higher energy levels; light is emitted as they fall back, with the colour determined by the specific energy gap.
Concept context
Group 1 (alkali metals) and Group 2 (alkaline earth metals). Learn their reactions with water and air, important compounds like NaOH, Na₂CO₃, and CaCO₃, and anomalous behaviour of lithium and beryllium.