6.1. Na and Mg with water

Question 1

Sodium with water

Answer 1

2Na (s) + 2H2O (l) → 2NaOH (aq) + H2 (g)

• Vigorous and exothermic
• Melts into ball fizzing across waters surface until it disappears
• H2 gas given off
• Strongly alkaline solution formed because of the NaOH formed
• Colourless

Question 2

Magnesium with Water

Answer 2

• Mg (s) + 2H2O (l) → Mg(OH)2 (aq) + H2 (g)
• Weakly alkaline solution, Mg(OH)2 only slightly soluble
• when heated in steam, reacts vigorously to for MgO and H2
• Mg (s) + H2O (g) → MgO (s) + H2 (g)
• Burn with whit flame