Question

What was the percent strenght of 200ml of stock solution if it was diluted to 1% 500ml?

Answer 1

To find the percent strength of the original stock solution, we can use the concept of dilution. The formula for dilution is given by:

\[
C_1 \times V_1 = C_2 \times V_2
\]

where:
- \( C_1 \) is the concentration of the stock solution,
- \( V_1 \) is the volume of the stock solution used,
- \( C_2 \) is the concentration of the diluted solution,
- \( V_2 \) is the volume of the diluted solution.

In your case:
- \( C_2 = 1\% \)
- \( V_2 = 500 \, \text{ml} \)
- \( V_1 = 200 \, \text{ml} \)

We need to find \( C_1 \).

Substituting the known values into the dilution equation:

\[
C_1 \times 200 \, \text{ml} = 1\% \times 500 \, \text{ml}
\]

Calculating the right side:

\[
1\% \times 500 \, \text{ml} = 0.01 \times 500 = 5 \, \text{ml}
\]

Now we have:

\[
C_1 \times 200 \, \text{ml} = 5 \, \text{ml}
\]

To solve for \( C_1 \):

\[
C_1 = \frac{5 \, \text{ml}}{200 \, \text{ml}} = 0.025
\]

To express \( C_1 \) as a percentage:

\[
C_1 = 0.025 \times 100\% = 2.5\%
\]

Therefore, the percent strength of the 200 ml of the stock solution is **2.5%**.