It’s B. Chromium(III) oxide
Answer : The balanced chemical equation is,

Explanation :
Balanced chemical equation : It is defined as the number of atoms of individual elements present on the reactant side must be equal to the number of atoms of individual elements present on product side.
The given unbalanced chemical reaction is,

This chemical reaction is an unbalanced reaction because in this reaction, the number of atoms of individual elements are not balanced.
In order to balanced the chemical reaction, the coefficient 2 is put before the
, the coefficient 3 is put before the
and the coefficient 4 is put before the
.
The energy evolved in this reaction = 
Thus, the balanced chemical reaction will be,

POH of a 0.0072 M=-lg(0.0072) = 2.1426675
Answer:
116.3 grCO2
Explanation:
1st - we balance the equation so that it finds the same amount of elements of the product side and of the reagent side
C6H6 +15/2 O2⟶ 6CO2 +3 H2O
2nd - we calculate the limiting reagent
39.2gr C6H6*(240grO2/78grC6H6)=120 grO2
we don't have that amount of oxygen so this is the excess reagent and oxygen the limiting reagent
3rd - we use the limiting reagent to calculate the amount of CO2 in grams
105.7grO2*(264grCO2/240grO2)=116.3 grCO2
I can tell you're not very educated because everyone knows that breathing pure oxygen for long periods of time can sometimes hurt us. Oxygen in lower levels, such as levels found in atmosphere are just right for us to breathe. Get a life and stop trying to scare young kids that just want help on their homework.