The correct statement amongst the following is :

The correct statement amongst the following is :
  1. The term 'standard state' implies that the temperature is $0^{\circ} \mathrm{C}$
  2. The standard state of pure gas is the pure gas at a pressure of 1 bar and temperature 273 K
  3. $\Delta_{\mathrm{f}} \mathrm{H}_{298}^\theta$ is zero for $\mathrm{O}(\mathrm{g})$
  4. $\Delta_{\mathrm{f}} \mathrm{H}_{500}^\theta$ is zero for $\mathrm{O}_2(\mathrm{~g})$

Solution

For standard state $\Rightarrow$ pressure $=1$ bar and temperature is specified only
$\Rightarrow\left(\Delta \mathrm{H}_{\mathrm{f}}^{\mathrm{o}}\right)_{\mathrm{O}_{2,(\mathrm{~g})}}=0$

Asked in: JEE Main 2025 (07 Apr Shift 2)

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