A vessel contains 16 g of hydrogen and 128 g of oxygen at standard temperature and pressure. The volume of the vessel in cm³ is :

No of moles of H₂ = 8 moles 

No of moles of O₂ = 4 moles  

Total moles = 12 moles 

At STP, volume occupied by 1 mole = 22.4 L = 22.4 × 10³ cm³ 

At STP, volume occupied by 12 moles = 12 × 22.4 × 10³ cm³  = 26.88 × 10⁴ cm³  =27 × 10⁴ cm³