Determining the Unknown Concentration of Nitric Acid

What is the unknown concentration of nitric acid?

Given that 35.0 mL of 0.255 M nitric acid is added to 45.0 ml of nitric acid of unknown concentration, and the final solution is 0.255 M.

Answer:

The unknown concentration of nitric acid is 0.374 M.

By using the concept of dilution and equating the moles of nitric acid in the initial and final solutions, we can find the unknown concentration to be 0.374 M.

To determine the unknown concentration of nitric acid, we can use the concept of dilution. The moles of nitric acid in the initial solution can be calculated using the given volume and concentration. Then, using the final volume and concentration, we can find the moles of nitric acid in the final solution. Equating the moles of nitric acid in the initial and final solutions, we can solve for the unknown concentration.

Let's calculate the moles of nitric acid in the initial solution:

Moles of HNO₃ = Volume * Concentration

= (35.0 mL * 0.255 M)

= 8.925 mmol of HNO₃

Now, let's calculate the moles of nitric acid in the final solution:

Moles of HNO₃ = Volume * Concentration

= (35.0 mL + 45.0 mL) * 0.255 M

= 23.85 mmol of HNO₃

Since the moles of nitric acid are the same in both the initial and final solutions, we can write the equation:

8.925 mmol = 23.85 mmol * Unknown Concentration

Unknown Concentration = 8.925 mmol / 23.85 mmol

Unknown Concentration = 0.374 M