Multiple choice

If a volume of a mixture of ${CO}{2}$ and $CO$ increases by $20$% on passing over hot coke, the percentage of ${CO}{2}$ in the original mixture is: $\left( C+{ CO }_{ 2 }\longrightarrow 2CO \right) $

  1. $10$%
  2. $15$%
  3. $20$%
  4. $25$%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let initial moles be x (CO2) and y (CO). Total = x+y. Reaction: CO2 + C -> 2CO. If x moles of CO2 react, they produce 2x moles of CO. Net change in moles = +x. Increase = x / (x+y) = 0.20. x = 0.2x + 0.2y. 0.8x = 0.2y. y = 4x. Total = 5x. %CO2 = x/5x = 20%.

AI explanation

Let the initial volume of the mixture be V, where the volume of CO2 is x and the volume of CO is (V minus x). According to the reaction CO2 plus C forms 2CO, the x liters of CO2 is converted into 2x liters of CO, making the final total volume V plus x. Since a 20 percent increase means the final volume is 1.2 times V, the equation V plus x equals 1.2 times V yields x equals 0.2 times V, showing the original mixture is 20 percent CO2.

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