Answer: Mg(OH)2.
- A Mg(OH)2
- B MgO
- C MgCO3
- D MgSO4
Correct answer: A. Mg(OH)2
Explanation: Milk of magnesia is a suspension of magnesium hydroxide Mg(OH)2 in water, used as an antacid and laxative.
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.