JEE Main 2012 Chemistry question

When is passed over red hot coke it partially gets reduced to CO(g). Upon passing 0.5 L of over red hot coke, the total volume of the gases increased to 700 mL. The composition of the gaseous mixture at STP is

• (1) = 300 mL; CO = 400 mLCorrect
• (2) = 0.0 mL; CO = 700 mL
• (3) = 200 mL; CO = 500 mL
• (4) = 350 mL; CO = 350 mL