You want to determine the concentration when 93 mL of a 2.03 M KF solution is diluted by adding [tex]3920 \, \text{mL} \, \text{H}_2\text{O}[/tex].

[tex]\[ \begin{array}{c}
M_1 = 2.03 \, \text{M} \quad V_1 = 93 \, \text{mL} \\
M_2 = ? \, \text{M} \quad V_2 = 4013 \, \text{mL} \\
M_1 V_1 = M_2 V_2
\end{array} \][/tex]

What is the molarity of the diluted solution?

[?] M



Answer :

To determine the concentration of a solution after dilution, we use the dilution equation:

[tex]\[ M_1 \times V_1 = M_2 \times V_2 \][/tex]

where:
- [tex]\( M_1 \)[/tex] is the initial molarity of the solution
- [tex]\( V_1 \)[/tex] is the initial volume of the solution
- [tex]\( M_2 \)[/tex] is the final molarity of the solution after dilution
- [tex]\( V_2 \)[/tex] is the final volume of the solution after dilution

Given the problem:
- [tex]\( M_1 = 2.03 \, \text{M} \)[/tex]
- [tex]\( V_1 = 93 \, \text{mL} \)[/tex]
- [tex]\( V_2 = V_1 + \text{volume of water added} = 93 \, \text{mL} + 3920 \, \text{mL} = 4013 \, \text{mL} \)[/tex]

We need to find [tex]\( M_2 \)[/tex].

Step-by-step solution:
1. Write down the dilution equation:
[tex]\[ M_1 \times V_1 = M_2 \times V_2 \][/tex]

2. Substitute the known values into the equation:
[tex]\[ 2.03 \, \text{M} \times 93 \, \text{mL} = M_2 \times 4013 \, \text{mL} \][/tex]

3. To isolate [tex]\( M_2 \)[/tex], divide both sides of the equation by [tex]\( V_2 \)[/tex]:
[tex]\[ M_2 = \frac{2.03 \times 93}{4013} \][/tex]

4. Calculate the right-hand side:
[tex]\[ M_2 = \frac{188.79}{4013} \][/tex]

5. Perform the division:
[tex]\[ M_2 \approx 0.047 \][/tex]

6. Therefore, the molarity of the diluted solution is approximately:
[tex]\[ M_2 \approx 0.047 \, \text{M} \][/tex]

So the molarity of the diluted KF solution is approximately [tex]\( 0.047 \, \text{M} \)[/tex].