- 2069 Bhadra · 5 marks
Primary and low explosives; TNT and TNG
Short answer
Primary explosives (lead azide) are crucial in detonators to initiate secondary charges; low explosives (black powder) provide propelling force for guns, rockets, and soft blasting. TNT is made by nitrating toluene with HNO₃/H₂SO₄ and used in shells, bombs, mining. TNG (nitroglycerine) is made by nitrating glycerol below 15°C and used in dynamite, cordite, and as a medicine.
Mention the importance of primary and low explosives. Give the preparation and uses of TNT and TNG.
Importance
- Primary explosives (lead azide, mercury fulminate) are essential in detonators and primers, because they explode easily and start the main charge of safer high explosives.
- Low explosives (black powder, smokeless powder) are valuable as propellants in guns and rockets, in fireworks, safety fuses, and for blasting soft rocks and coal where shattering is unwanted.
TNT
Prepared by nitration of toluene with conc. HNO₃ and conc. H₂SO₄ in three stages (30 °C, 60 °C, 100–110 °C): C₆H₅CH₃ + 3HNO₃ → C₆H₂(CH₃)(NO₂)₃ + 3H₂O Uses: shells, bombs, mining and demolition.
TNG (glycerol trinitrate)
Prepared by adding glycerol to conc. HNO₃ + conc. H₂SO₄ below 10–15 °C: C₃H₅(OH)₃ + 3HNO₃ → C₃H₅(ONO₂)₃ + 3H₂O Uses: dynamite, gelignite, cordite, blasting, and angina medicine.
✓ Answer checked by Claude Opus 5.5 (high effort)
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