Question

How many litres of O\(_2\) at 273 K and 1 atm pressure can give 20 L of CO in the following reaction?
\[ C + O_2 \rightarrow CO_2 \rightarrow CO \]

• A. 40 L
• B. 20 L
• C. 5 L
• D. 10 L

Hint:

At STP, volume ratios of gases are directly proportional to mole ratios in the balanced chemical equation.

Answer 1

The Correct Option is D

Step 1: Reaction stoichiometry.
2C + O₂ → 2CO, so 1 volume of O₂ yields 2 volumes of CO.

Step 2: Mole-volume equivalence at STP.
At 273 K and 1 atm, volume ratios equal mole ratios.

Step 3: Using the given CO amount.
20 L CO corresponds to half that volume of O₂.

Step 4: Oxygen volume computation.
V(O₂) = 20/2 = 10 L.

Step 5: Confirmation.
STP conditions validate direct volume-ratio application.

Step 6: Conclusion.
Hence, 10 L of oxygen is required.