The molar mass of KCl is [tex]74.55 \, \text{g/mol}[/tex]. If 8.45 g of KCl are dissolved in 0.750 L of solution, what is the molarity of the solution?

Use the formula for molarity: [tex]\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}[/tex].

A. 0.113 M
B. 0.151 M
C. 6.62 M
D. 11.3 M



Answer :

To determine the molarity of the given KCl solution, we need to follow these steps:

1. Find the moles of KCl:

First, we need to calculate the number of moles of KCl. We can do this by using the formula:

[tex]\[ \text{moles of KCl} = \frac{\text{mass of KCl}}{\text{molar mass of KCl}} \][/tex]

Given data:
- Mass of KCl = 8.45 g
- Molar mass of KCl = 74.55 g/mol

Substituting the values:

[tex]\[ \text{moles of KCl} = \frac{8.45 \text{ g}}{74.55 \text{ g/mol}} \approx 0.113 \][/tex]

So, the moles of KCl are approximately [tex]\(0.113 \text{ mol}\)[/tex].

2. Calculate the molarity of the solution:

The molarity (M) is calculated using the formula:

[tex]\[ \text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liters of solution}} \][/tex]

Given data:
- Volume of the solution = 0.750 L

Substituting the values:

[tex]\[ \text{Molarity (M)} = \frac{0.113 \text{ mol}}{0.750 \text{ L}} \approx 0.151 \text{ M} \][/tex]

Therefore, the molarity of the solution is approximately [tex]\(0.151 \text{ M}\)[/tex].

From the provided options, the correct molarity is:

[tex]\[ \boxed{0.151 \text{ M}} \][/tex]