What will be the mass percentage of resulting solution prepared by mixing 15% (w/w) 500g aqueous solution of urea with 25% (w/w)
400g aqueous solution of it :-

Options

A. 0.18
B. 0.2
C. 0.25
D. 0.15

Explanation

To find the mass percentage of the resulting solution prepared by mixing 15% (w/w) 500g aqueous solution of urea with 25% (w/w) 400g aqueous solution of urea, we can follow these steps:

### Step 1: Calculate the mass of urea in the first solution
The first solution is 15% (w/w) urea in a 500g solution.

\[ \text{Mass of urea in first solution} = \frac{15}{100} \times 500 = 75 \text{ grams} \]

### Step 2: Calculate the mass of urea in the second solution
The second solution is 25% (w/w) urea in a 400g solution.

\[ \text{Mass of urea in second solution} = \frac{25}{100} \times 400 = 100 \text{ grams} \]

### Step 3: Calculate the total mass of urea
Now, we can find the total mass of urea by adding the masses from both solutions.

\[ \text{Total mass of urea} = 75 + 100 = 175 \text{ grams} \]

### Step 4: Calculate the total mass of the resulting solution
The total mass of the resulting solution is the sum of the masses of both solutions.

\[ \text{Total mass of solution} = 500 + 400 = 900 \text{ grams} \]

### Step 5: Calculate the mass percentage of urea in the resulting solution
The mass percentage of urea in the resulting solution can be calculated using the formula:

\[ \text{Mass percentage} = \left( \frac{\text{Mass of solute}}{\text{Mass of solution}} \right) \times 100 \]

Substituting the values we calculated:

\[ \text{Mass percentage} = \left( \frac{175}{900} \right) \times 100 \approx 19.44\% \]

### Step 6: Round the mass percentage
Since the options may not include 19.44%, we can approximate it to 20%.

### Final Answer
The mass percentage of the resulting solution is approximately **20%**.

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