Consider the following statements regarding the comparison of PNG (Piped Natural Gas) and LPG (Liquefied Petroleum Gas):
- PNG is lighter than air and therefore spreads upwards in case of leakage, whereas LPG is heavier than air and therefore collects near the ground.
- PNG always provides more energy per unit weight than LPG.
- The pressure of PNG is generally lower than that of LPG.
Which of the above statements are correct?
Correct answer: B
Explanation
PNG is mostly methane, which is lighter than air and disperses upward on leakage, while LPG is heavier and pools near the ground, so statement 1 holds. PNG is also supplied at much lower pressure than LPG cylinders, so statement 3 holds. Statement 2 is the trap: the blanket claim that PNG "always" gives more energy per unit weight than LPG is false, since LPG is the more energy-rich domestic fuel.