Answer:
pH = 12.35
Explanation:
The HCl reacts with NaOH, thus:
HCl + NaOH → NaCl + H₂O
1 mole of HCl reacts per mole of NaOH
To know the pH we must know the moles of NaOH and the moles of HCl that reacts
Moles NaOH and HCl
NaOH: 0.0280L * (0.230mol / L) = 6.44x10⁻³ moles
HCl: 0.0230L * (0.230mol / L) = 5.29x10⁻³
As moles NaOH > Moles HCl, the moles that remains of NaOH are:
Moles NaOH = 6.44x10⁻³ - 5.29x10⁻³ = 1.15x10⁻³ moles NaOH = Moles OH⁻
In 23.0mL + 28.0mL = 51.0mL = 0.0510L:
1.15x10⁻³ moles OH⁻ / 0.0510L =
0.0225M OH⁻
pOH = -log [OH⁻]
pOH = 1.647
And pH = 14 - pOH
pH = 12.35
