At $300 K$ , a $2.0 L$ flask contains $CO$ at $0.50 atm$ and a $3.0 L$ flask contains $O X_{2}$ at $1.0 atm$ . The flasks are connected and the gases react completely by $2 CO + O X_{2} 2 CO X_{2}$ , the temperature returning to $300 K$ . Which statements are correct?

ABefore reaction, the partial pressure of $CO$ in the combined $5.0 L$ is $0.20 atm$
B $CO$ is the limiting reagent
CThe final partial pressure of $CO X_{2}$ is $0.20 atm$
DThe final total pressure is $0.70 atm$

Answer: A, B, C, D

p_{CO} = 0.50 \times 2/5 = 0.20

p_{O X_{2}} = 1.0 \times 3/5 = 0.60 atm

(A).

0.20

CO needs

0.10

O X_{2}

, so CO is limiting (B) and gives

0.20 atm

CO X_{2}

(C). Final:

O X_{2}

0.50 + CO X_{2}

0.20 = 0.70 atm

(D). All correct.