When one mole each of CO and `O_(2)` are made to react at STP, the total number of moles at the end of the reactions is

Options

A. `1.5` moles
B. 1 mole
C. 4 mole
D. 2 moles

Answer

To solve the problem of determining the total number of moles at the end of the reaction between one mole of CO and one mole of O₂ at STP, we can follow these steps:

### Step 1: Write the balanced chemical equation for the reaction.
The reaction between carbon monoxide (CO) and oxygen (O₂) produces carbon dioxide (CO₂). The balanced equation is:
\[ 2 \text{CO} + \text{O}_2 \rightarrow 2 \text{CO}_2 \]

### Step 2: Determine the initial moles of reactants.
Initially, we have:
- 1 mole of CO
- 1 mole of O₂

### Step 3: Use the stoichiometry of the balanced equation to find out how much of each reactant is consumed.
From the balanced equation, we see that 2 moles of CO react with 1 mole of O₂. Therefore, for 1 mole of CO, we need:
\[ \frac{1}{2} \text{ mole of O}_2 \]

### Step 4: Calculate the remaining moles of each reactant after the reaction.
- CO is completely consumed:
- Remaining moles of CO = 1 - 1 = 0 moles
- O₂ consumed = 0.5 moles (since only half a mole is required for 1 mole of CO):
- Remaining moles of O₂ = 1 - 0.5 = 0.5 moles

### Step 5: Determine the moles of product formed.
From the balanced equation, 1 mole of CO produces 1 mole of CO₂. Therefore:
- Moles of CO₂ formed = 1 mole

### Step 6: Calculate the total number of moles at the end of the reaction.
Now, we can sum the remaining moles of the reactants and the moles of the product:
- Remaining moles of CO = 0
- Remaining moles of O₂ = 0.5
- Moles of CO₂ = 1

Total moles at the end of the reaction:
\[ \text{Total moles} = 0 + 0.5 + 1 = 1.5 \]

### Final Answer:
The total number of moles at the end of the reaction is **1.5 moles**.

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