The GATE Grind

GATE 2025 MN – Question 23

Surface Environment, Mine Ventilation and Underground Hazards · Underground Hazards · 1 mark · Multiple choice

Which pair is used in a traditional chemical-foam fire extinguisher?

  1. NaHCO₃ and Na₂SO₄
  2. Al₂(SO₄)₃ and Na₂SO₄
  3. Al₂(SO₄)₃ and Al(OH)₃
  4. NaHCO₃ and Al₂(SO₄)₃

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (D) NaHCO₃ and Al₂(SO₄)₃

Explanation

The traditional reaction uses sodium bicarbonate with aluminium sulphate, D, producing carbon dioxide that creates the foam with its stabilising medium. The other pairs omit one of those reacting components. The question concerns the older chemical-foam type, not all modern foam systems.

More Underground Hazards questions

All Underground Hazards questions →