The Apparatus Shown Is Called a Closed-End Manometer Because the Arm

Multiple Choice

The apparatus shown is called a closed-end manometer because the arm not connected to the gas sample is closed to the atmosphere and is under vacuum.
-What is the pressure (in mm Hg) of the gas inside the above apparatus if the outside pressure,P_atm,is 750 mm Hg and the difference in mercury levels,Δh,is 25 mm Hg?

A) 25 mm Hg
B) 725 mm Hg
C) 750 mm Hg
D) 775 mm Hg