Correct Answer - D
We know that from the reaction `H_(2)+Cl_(2) rarr 2HCl` that the ratio of the volume of gaseous reactants and products is in agreement with their molar ratio. The ratio of `H_(2):Cl_(2):HCl` volumes is `1:1:2` which is the same as their molar ratio. Thus volume of gas is directly related to the number of moles. Therefore, the assertion is false but reason is true.