Your dimensions are not sufficient. 25 liters is not an accurate measure of calcium oxide. It should be either a solution with a specific concentration or a mass.
"Limiting reagents" are those that are used up first in a reaction, leaving some of the other reagents in excess. In this problem the excess is already stated, which means that we only need to calculate the maximum yield of the product from the given limiting reagent, calcium oxide.
However, the dimension given for the calcium oxide is not accurate, as it could have any range of densities. The best dimension for reactions is mass. A defined concentration of a solution is the next best form.