nₐCₐVₐ = n_bC_bV_b
Neutralization occurs when an acid reacts with a base to form water and a salt. At the equivalence point, moles of H⁺ = moles of OH⁻. For polyprotic acids or polyhydroxy bases, the equation is nₐCₐVₐ = nbCbVb, where n = number of ionizable protons/hydroxides. For HCl + NaOH (both n=1): CₐVₐ = CbVb. For H₂SO₄ + NaOH: 2CₐVₐ = CbVb. The heat of neutralization for strong acid–strong base is approximately −57.1 kJ/mol (the enthalpy of H⁺ + OH⁻ → H₂O). Weak acid/base neutralizations have different heats because dissociation energy must be supplied. Applications: titration analysis, antacid dosing, wastewater pH adjustment, and industrial chemical processing.