In order to determine the mole ratio, we need to begin with a balanced chemical equation.
For this reaction the balanced chemical equation is
2
H
2
+
O
2
→
2
H
2
O
The mole ratios are determined using the coefficients of the substances in the balanced chemical equation.
2
m
o
l
H
2
:
1
m
o
l
O
2
:
2
m
o
l
H
2
O
The mole ratio for
O
2
H
2
O
is:
2
m
o
l
H
2
:
1
m
o
l
O
2
2
m
o
l
H
2
1
m
o
l
O
2
or
1
m
o
l
O
2
2
m
o
l
H
2
1
m
o
l
O
2
:
2
m
o
l
H
2
O
1
m
o
l
O
2
2
m
o
l
H
2
O
or
2
m
o
l
H
2
O
1
m
o
l
O
2
I hope this was helpful.