Gasoline use contributes to air pollution
Gasoline is a toxic and highly flammable liquid. The vapors given off when gasoline evaporates and the substances produced when gasoline is burned (carbon monoxide, nitrogen oxides, particulate matter, and unburned hydrocarbons) contribute to air pollution. Burning gasoline also produces carbon dioxide, a greenhouse gas.
Evaporation of the solution
Balance the reaction first:
3KOH + H3PO4 —> K3PO4 + 3H2O
So for every mol of H3PO4, you need 3 mol of OH- to fully neutralize the acid, since H3PO4 is polyprotic.
0.0200 L KOH • (2.000 mol KOH / L KOH) • (1 mol H3PO4 / 3 mol KOH) = 0.0133 mol H3PO4
Divide this by the volume of H3PO4 to get the concentration.
0.0133 mol H3PO4 / 0.0250 L = 0.532 M H3PO4