20 cm ³ of hydrogen gas are sparked with 20cm ³ of oxygen gas in an endimoeter at 373k (100 ^oC) and 1 atmosphere. The resulting mixture is cooled to 298 K (25 ^oC) and passed over calcium chloride. The volume of the residual gas is

• A.40 cm ³
• B.20 cm ³
• C.30 cm ³
• D.10cm ³
• E.5cm ³