Which of the following compounds provides the most solute particles when completely dissociated in water?
a) Na3P because it dissociates into four ions.
b) NaCl because the mass of the formula unit is the smallest.
c) MgCl2 because the mass of the particles is greater.
d) NH4 because it dissociates into five ions.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.