Chemistry – Stoichiometry - The mole and the Avogadro constant | e-Consult

1. Write the balanced chemical equation:

HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

2. Calculate the moles of HCl in the original solution:

Concentration of HCl = moles / volume. We need to assume a concentration for the HCl solution. Let's assume the HCl solution is 1.0 mol/dm³. Then, moles of HCl = (1.0 mol/dm³) * (0.025 dm³) = 0.025 mol

3. Use the stoichiometry of the balanced equation to find the moles of NaOH:

From the equation, the mole ratio of HCl to NaOH is 1:1. Therefore, moles of NaOH = moles of HCl = 0.025 mol

4. Calculate the concentration of the NaOH solution:

Concentration of NaOH = moles / volume = 0.025 mol / 0.020 dm³ = 1.25 mol/dm³

Answer: The concentration of the sodium hydroxide solution is 1.25 mol/dm³.