2.5 litre of 1 M NaOH solution are mixed with another 3 litre of 0.5 M NaOH solution Then the molarity of the resulting

Options

A. 0.80 M
B. 1.0 M
C. 0.73 M
D. 0.50 M

Explanation

To find the molarity of the resulting solution when mixing two NaOH solutions, we can follow these steps:

### Step 1: Calculate the number of moles of NaOH in each solution.

1. **For the first solution (2.5 L of 1 M NaOH):**
\[ \text{Moles of NaOH}_1 = M_1 \times V_1 = 1 \, \text{mol/L} \times 2.5 \, \text{L} = 2.5 \, \text{moles} \]

2. **For the second solution (3 L of 0.5 M NaOH):**
\[ \text{Moles of NaOH}_2 = M_2 \times V_2 = 0.5 \, \text{mol/L} \times 3 \, \text{L} = 1.5 \, \text{moles} \]

### Step 2: Calculate the total number of moles of NaOH.

\[ \text{Total moles of NaOH} = \text{Moles of NaOH}_1 + \text{Moles of NaOH}_2 = 2.5 + 1.5 = 4.0 \, \text{moles} \]

### Step 3: Calculate the total volume of the resulting solution.

\[ \text{Total volume} = V_1 + V_2 = 2.5 \, \text{L} + 3 \, \text{L} = 5.5 \, \text{L} \]

### Step 4: Calculate the molarity of the resulting solution.

\[ \text{Molarity of resulting solution} = \frac{\text{Total moles of NaOH}}{\text{Total volume}} = \frac{4.0 \, \text{moles}}{5.5 \, \text{L}} \approx 0.727 \, \text{M} \]

### Final Answer:
The molarity of the resulting solution is approximately **0.73 M**.

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