The molarity of a solution obtained by mixing 800 mL of 0.5 M HCl with 200 mL of 1 M HCl will be

Options

A. 0.8 M
B. 0.6 M
C. 0.4 M
D. 0.2 M

Explanation

To find the molarity of the solution obtained by mixing 800 mL of 0.5 M HCl with 200 mL of 1 M HCl, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the volumes and molarities of the solutions being mixed:**
- Volume of HCl solution 1 (V1) = 800 mL
- Molarity of HCl solution 1 (M1) = 0.5 M
- Volume of HCl solution 2 (V2) = 200 mL
- Molarity of HCl solution 2 (M2) = 1 M

2. **Calculate the number of moles of HCl in each solution:**
- Moles of HCl from solution 1 (n1) = M1 × V1 = 0.5 M × 0.800 L = 0.4 moles
- Moles of HCl from solution 2 (n2) = M2 × V2 = 1 M × 0.200 L = 0.2 moles

3. **Calculate the total number of moles of HCl after mixing:**
- Total moles of HCl (n_total) = n1 + n2 = 0.4 moles + 0.2 moles = 0.6 moles

4. **Calculate the total volume of the mixed solution:**
- Total volume (V_total) = V1 + V2 = 800 mL + 200 mL = 1000 mL = 1 L

5. **Calculate the molarity of the final solution:**
- Molarity of the mixed solution (M3) = Total moles of HCl / Total volume in liters
- M3 = n_total / V_total = 0.6 moles / 1 L = 0.6 M

### Final Answer:
The molarity of the solution obtained by mixing the two solutions is **0.6 M**.

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