Answer:
is the limiting reagent and
is the excess reagent.
Step-by-step explanation:
The balanced chemical reaction is :
According to stoichiometry :
1 mole of
require = 2 moles of

Thus 0.250 moles of
will require=
of

As
present is more than the required amount , it is an excess reagent.
Thus
is the limiting reagent as it limits the formation of product and
is the excess reagent.