Question

Determine the concentration of a phosphoric acid solution if a 25.00 mL sample of phosphoric acid of unknown concentration requires 35.77 mL of a 0.250 M NaOH solution to reach the equivalence point.

Answer 1

To determine the concentration of the hydrochloric acid solution, we can use the equation: mol HCl = mol NaOH. Using the given volume and concentration of NaOH, we can calculate the number of moles of NaOH and then determine the concentration of the HCl solution.

Step-by-step explanation:

To determine the concentration of the hydrochloric acid solution, we can use the equation:

mol HCl = mol NaOH

Since we know the volume and concentration of the NaOH solution that is required to reach the equivalence point (endpoint), we can calculate the number of moles of NaOH:

mol NaOH = volume NaOH (L) * concentration NaOH (M)

Substituting the given values, we have:

mol NaOH = 0.031416 L * 0.1234 M = 0.00388 mol NaOH

Since the equation is 1:1, the number of moles of HCl is also 0.00388 mol. Now, we can calculate the concentration of the HCl solution:

concentration HCl = mol HCl / volume HCl (L)

Given that the volume of the HCl solution is 0.200 L:

concentration HCl = 0.00388 mol / 0.200 L = 0.0194 M

Answer 2

Answer: The concentration of given phosphoric acid solution is 0.357 M.

Step-by-step explanation:

Given:
`V_(1)` = 25.00 mL,
`M_(1) = ?`

`V_(2)` = 35.77 mL,
`M_(2)` = 0.250 M

Formula used to calculate the concentration of phosphoric acid is as follows.

`M_(1)V_(1) = M_(2)V_(2)`

Substitute the values into above formula as follows.

`M_(1)V_(1) = M_(2)V_(2)\\M_(1) * 25.00 mL = 0.250 M * 35.77 mL\\M_(1) = 0.357 M`

Thus, we can conclude that concentration of given phosphoric acid solution is 0.357 M.