Question

Analysis of the water content of a lake found in the desert showed that it contained 16.6 percent chloride ion, and had a density of 1.23 g/mL. What is the molarity of the chloride ion in the water

Answer 1

Answer : The molarity of the chloride ion in the water is, 5.75 M

Explanation :

As we are given that 16.6 % chloride ion that means 16.6 grams of chloride ion present 100 grams of solution.

First we have to calculate the volume of solution.

$\text{Volume of solution}=\frac{\text{Mass of solution}}{\text{Density of solution}}$

$\text{Volume of solution}=\frac{100g}{1.23g/mL}=81.3mL$

Now we have to calculate the molarity of chloride ion.

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Mass of chloride ion}\times 1000}{\text{Molar mass of chloride ion}\times \text{Volume of solution (in mL)}}$

Now put all the given values in this formula, we get:

$\text{Molarity}=\frac{16.6g\times 1000}{35.5g/mole\times 81.3mL}=5.75mole/L=5.75M$

Thus, the molarity of the chloride ion in the water is, 5.75 M