A vessel contains 16g of hydrogen and 128g of oxygen at standard...

Number of moles of Hydrogen $\left({H}_{2}\right) = \dfrac{m}{M} = \dfrac{16}{2} = 8$

Number of moles of oxygen \left({O}_{2}\right) = \dfrac{128}{32} = 4$</p><p>Using ideal gas equation,$PV = nRT$,</p><p>Where pressure$P = 1atm = 1 . 01 \times {10}^{5}Pa\left(STP\right)$</p><p>Putting the values, </p><p>$1 . 01 \times {10}^{5}V = \left(8 + 4\right) \times 8 . 314 \times 273$</p><p>$V = \dfrac{12 \times 8 . 314 \times 273}{1 . 01 \times {10}^{5}}{m}^{3}$</p><p>$= 0 . 27 \times {10}^{6}{cm}^{3} = 27 \times {10}^{4}{cm}^{3}