Q.A combustible gas is stored in a metal tank at a pressure of 2.98 atm at 25 $^\circ$C. The tank can withstand a maximum pressure of 12 atm after which it will explode. The building in which the tank has been stored catches fire. Now predict whether the tank will blow up first or start melting? (Melting point of the metal = 1100 K).

Step 1. The tank is a sealed, fixed-volume container, so Gay-Lussac's law applies: $\dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}$.

Step 2. Find the temperature at which the internal pressure would reach the tank's maximum, 12 atm. Given $P_1=2.98\ \text{atm}$ at $T_1=25+273=298$ K, and $P_2=12\ \text{atm}$: $T_2=\dfrac{P_2T_1}{P_1}=\dfrac{12\times298}{2.98}=\dfrac{3576}{2.98}=1200$ K.

Step 3. So the gas pressure would only reach the tank's 12 atm bursting point at 1200 K. …

Use Gay-Lussac's law to find the temperature at which the internal pressure would reach the tank's explosion limit, then compare that temperature against the given …

• Comparing the given pressures/temperatures directly without actually computing the temperature at which 12 atm is reached, and so missing that it comes out to a clean, checkable 1200 K. …