In another experiment, the student titrated 50.0mL of 0.100MHC2H3O2 with 0.100MNaOH(aq) . Calculate the pH of the solution at the equivalence point.

Respuesta :

pH=8.87

Further explanation

Reaction

C₂H₄O₂+NaOH⇒CH₃COONa+H₂O

at the equivalence point = mol C₂H₄O₂= mol NaOH

mol C₂H₄O₂ : 50 x 0.1 = 0.5 mlmol=5.10⁻⁴ mol

The two reactants have completely reacted, and there is only salt(CH₃COONa) and water(H₂O), there will be hydrolysis

For acids from weak acids and strong bases (the solution is alkaline) then the calculation:

[tex]\tt [OH^-]=\sqrt{\dfrac{Kw}{Ka}\times M }[/tex]

M=anion concentration=CH₃COO⁻

Ka=acid constant(for CH₃COOH,Ka=1.8.10⁻⁵)

[tex]\tt [OH^-]=\sqrt{\dfrac{10^{-14}}{1.8.10^{-5}}\times 0.1 }[/tex]

[tex]\tt [OH^-]=\sqrt{5.6.10^{-11}}=7.483\times 10^{-6}[/tex]

pOH=6-log 7.483=5.13

pH= 14 - 5.13=8.87

The pH of the solution is the negative log [H] concentration. The pH of the given solution is 8.87 at the equivalence point.

pH:

The given Reaction is:  

C₂H₄O₂+ NaOH ⇒ CH₃COON + H₂O

The pH of the solution can be calculated by,

[tex]\bold{pH = 14 - pOH}[/tex]................1

So first, calculate for pOH

[tex]\bold {pOH = \sqrt {\dfrac {Kw}{Ka} \times M}}[/tex]

Where,

Ka - dissociatioon constant = 50 x 0.1 = 0.5 ml = 5x10⁻⁴ mol

Kw - concentaion water ionic products = [tex]\bold {10^{-14}}[/tex]

M - anion concentration( CH₃COO⁻) = 0.1 M

Put the values in the formula,

[tex]\bold {pOH = \sqrt {\dfrac {\bold {10^{-14}}}{5\times 10^{-4} mol} \times 0.1}}\\\\\bold {pOH = 7.483 \times 10^{-6}}[/tex]

Since the pOH is the negative log of [OH⁻] concentration,

pOH = 6  -ln 7.483

pOH = 5.13

Put the value of pOH in the first equation,

pH= 14 - 5.13

pH = 8.87

Therefore, the pH of the given solution is 8.87 at the equivalence point.

Learn more about pH:

https://brainly.com/question/491373