Applying the Ideal Gas Law, we first want to check if all units match
R 0.082057 L atm mol^-1 K^-1

We will have to convert our temperature value
100.00 °C + 273.15 = 373.15 K

and our pressure from mm Hg to atm

700 mm Hg =

1 atm / 760 mm Hg

= 0.921 atm

Now, we're ready for pV = nRT

(0.921 atm)(2.50 L) = (x)

(0.082057 L atm) /             mole K

(373.15 K)

(0.921 atm)(2.5 L) = (x)

(30.6195 L atm) / mole

(x) =

(2.5 L)(0.921 atm) / (30.6195 L atm mole^-1)

x = 0.07519 moles


The number of moles is 0.0752
Answer D is the correct option