Hydrogen gas is used for many purposes, including the hydrogenation of vegetable oils to make margarine. The most common industrial process for producing hydrogen is "steam reforming," in which methane gas, CH4, from natural gas reacts with water vapor to form carbon monoxide gas and hydrogen gas.

a) CH4 (g) (1 mole) + H2O (g) (1 mole) = CO (g) + 3H2 (g) (3 moles).  

b) 3/1 or 3 will be the conversion factor used to convert moles of methane and the moles of hydrogen.  

c) Based on the given mole-mole relation,  

The number of moles of hydrogen produced by 1 mole of CH4 or methane is 3 moles. Therefore, the number of moles of hydrogen produced from 7 moles of CH4 would be,  

3/1 * 7 = 21 moles.  

d) The formation of 3 moles of hydrogen is taking place from 1 mole of water vapor or H2O. Therefore, the number of moles of water vapor required to produced 100.50 moles of hydrogen would be,  

1/3 * 100.50 moles = 33.5 moles.  

the answer is definitely c.