JEE Advanced 2024 Chemistry question on Surface Chemistry

To form a complete monolayer of acetic acid on 1g of charcoal, 100 mL of 0.5 M acetic acid was used. Some of the acetic acid remained unadsorbed. To neutralize the unadsorbed acetic acid, 40 mL of 1 M NaOH solution was required. If each molecule of acetic acid occupies P x $10^{-23}$ m$^2$ surface area on charcoal, the value of P is _____.
[Use given data: Surface area of charcoal = 1.5 x $10^{2}$ m$^2$g$^{-1}$; Avogadro's number (N$_A$) = 6.0 x $10^{23}$ mol$^{-1}$]