there's no picture here but I guess the answer would be:
considering the constant temperature, if you double the volume, the pressure would be halved.
like: volume is 2, pressure is 4
if 2×2, then:4÷2
Liquid, white,hm,wax,grey,sweet, white,minty,fresh,
The answer would be .5 mols because you take the total amount of grams, which is 20, and you had up the molar mass of sodium hydroxide, which would be 40. After you have this you would set this up as a stochiometry equation. With 1 mol on top you dived 20/40 to cancel out your grams. This leaves you with .5 mols