In a closed flask of 5 litres, 1.0 g of if H₂ is heated from 300 to 600 K. which statement is not correct

At constant V of a definite mass

$\frac{P_1}{T_1}=\frac{P_2}{T_2}\therefore \frac{P_1}{P_2}=\frac{300}{600}=\frac{1}{2}$ i.e., pressure increases

and on increasing temperature energy of molecules increases so the rate of collisions also increases and number of moles remains constant because there is neither addition nor removal of gas in the occurring.