Calculate the mass of a 20% nitric acid (HNO3) solution needed to neutralize a solution containing 80

Calculate the mass of a 20% nitric acid (HNO3) solution needed to neutralize a solution containing 80 grams of sodium hydroxide (NaOH).

HNO3 + NaOH = NaNO3 + H2O

Find the chemical amount of a substance: n = m / M

n (NaOH) = 80/40 = 2 mol

n (HNO3) = n (NaOH) = 2 mol, because ratio of ratios 1: 1.

We find the mass of a pure substance: m = n * M

m (HNO3) = 2 * (16 * 3 + 14 + 1) = 78 gr.

We find the mass of the solution: w = m (in-va) / m (pa-pa), therefore m (pa-pa) = m (in-va) / w, where w is not substituted in%, i.e. w = 20% / 100% = 0.2

m (pa-ra HNO3) = 78 / 0.2 = 198 gr.