Calculate the mass fraction of nitric acid in the solution if it is known that 180 g of this solution

Calculate the mass fraction of nitric acid in the solution if it is known that 180 g of this solution has completely reacted with 6 g of sodium hydroxide.

Given:
m solution (HNO3) = 180 g
m in islands (NaOH) = 6 g
To find:
w (HNO3)
Decision:
HNO3 + NaOH = NaNO3 + H2O
n (NaOH) = m / M = 6 g / 40 g / mol = 0.15 mol
n (NaOH): n (HNO3) = 1: 1
n (HNO3) = 0.15 mol
m in islands (HNO3) = n * M = 0.15 mol * 63 g / mol = 9.45 g
w (HNO3) = m in-va / m p-ra * 100% = 5.25%
Answer: 5.25%