To 20,00 ml of 0,0500 mol/l sulfuric acid solution 19,98 ml of 0,1000 mol/l
sodium hydroxide solution was added during titration. Calculate pH of the
solution.
Express numerical result with an accuracy of: Х,ХХ
To calculate the pH of the solution, we first need to determine the number of moles of sulfuric acid and sodium hydroxide that reacted.
The number of moles of sulfuric acid is given by:
moles of sulfuric acid = volume of sulfuric acid solution (L) * concentration of sulfuric acid (mol/L)
moles of sulfuric acid = 0.0200 L * 0.0500 mol/L
moles of sulfuric acid = 0.00100 mol
The number of moles of sodium hydroxide is given by:
moles of sodium hydroxide = volume of sodium hydroxide solution (L) * concentration of sodium hydroxide (mol/L)
moles of sodium hydroxide = 0.01998 L * 0.1000 mol/L
moles of sodium hydroxide = 0.001998 mol
Since sulfuric acid is a diprotic acid, it reacts with sodium hydroxide in a 1:2 ratio. This means that for every 1 mole of sulfuric acid, 2 moles of sodium hydroxide will react.
From the balanced chemical equation:
H2SO4 + 2NaOH -> Na2SO4 + 2H2O
Therefore, the number of moles of sulfuric acid that reacted is 0.00100 mol and the number of moles of sodium hydroxide that reacted is 2 * 0.00100 mol = 0.00200 mol.
The excess moles of sodium hydroxide is given by:
excess moles of sodium hydroxide = moles of sodium hydroxide added - moles of sodium hydroxide that reacted
excess moles of sodium hydroxide = 0.001998 mol - 0.00200 mol
excess moles of sodium hydroxide = -0.000002 mol
Since there is an excess of sodium hydroxide, the resulting solution is basic. To calculate the pH of a basic solution, we need to calculate the pOH and then convert it to pH.
The pOH can be calculated using the equation:
pOH = -log[OH-]
Since sodium hydroxide is a strong base, it dissociates completely, and the concentration of hydroxide ions ([OH-]) is equal to the concentration of sodium hydroxide.
[OH-] = concentration of sodium hydroxide
[OH-] = 0.1000 mol/L
Using this value, we can calculate the pOH:
pOH = -log(0.1000)
pOH ≈ 1.000
Finally, to calculate the pH, we use the equation:
pH = 14 - pOH
pH = 14 - 1.000
pH ≈ 13.000
Therefore, the pH of the solution is approximately 13.000.