Answer:
Theoretical 32.04 g
The precent yeild 87. 39 %
Step-by-step explanation:
Mole of H2 = m/mw = 4/2 = 2 mol
From the equation 
1 mol H2 --> 1/2 mol CH3OH
2 mol H2 -->?? 
So we have 1 mol Ch3oh 
Mass of Ch3oh = mole *Mw = 1* 32.04 
= 32.04g >>> the theoretically 
For percent yeild = actual / theoretical * 100%
( 28.0/32.04) *100% = 
87.93%