Answer: Electrolysis of molten NaCl (Down's process).
- A Electrolysis of molten NaCl (Down's process)
- B Chemical reduction with carbon under usual circumstances
- C Reaction with water according to most researchers
- D Solvay process in the majority of cases studied
Correct answer: A. Electrolysis of molten NaCl (Down's process)
Explanation: The Down's process electrolyses molten NaCl (with CaCl<sub>2</sub> to lower melting point) to obtain Na at the cathode and Cl<sub>2</sub> at the anode.
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.