A student mixes 50.0 mL of 0.20 M NaOH with 50.0 mL of 0.20 M HCl and predicts…
CHEMISTRY · Single correct · A Level · Chemistry · Amount of substance · Amount of substance
Problem
A student mixes 50.0 mL of 0.20 M NaOH with 50.0 mL of 0.20 M HCl and predicts complete neutralization because the two solutions contain the same amount of substance. Which statement best justifies the student’s comparison?
(a) Molarity is defined as mass per unit volume, so equal molarity and volume ensure the reactants have equal mass and therefore react completely.
(b) Using n=M×V, 0.20 M×50 mL=10, and because both values are 10 the two solutions contain equal moles of reactant.
(c) Multiplying a solution’s molarity by its volume yields the number of moles present, so equal values of those two variables indicate equal amounts of substance.
(d) By Avogadro’s law, equal volumes of any solutions at the same concentration contain the same number of particles, so the reactants are in a 1:1 mole ratio.