Respuesta :
Answer:
pH = 3.215
Explanation:
From the given information;
Using the equation for the dilution of a stock solution:
Since moles of C5H5N = moles of HNO3
Then:
[tex]M_{C_5H_5N}\times V_{C_5H_5N}= M_{HNO_3}\times V_{HNO_3}[/tex]
[tex]0.0750 M \times 2.65 L = 0.407 M \times V_{HNO_3}[/tex]
[tex]V_{HNO_3}= \dfrac{0.0750 M \times 2.65 L}{0.407 M}[/tex]
[tex]V_{HNO_3}=488.33 \ mL[/tex]
The reaction between C5H5NH and H2O is as follows:
[tex]C_5H_5N^+H + H_2O[/tex] ⇄ [tex]C_5H_5N + H_3O^+[/tex]
[tex]Molarity \ of \ C_5H_5N^+H = \dfrac{moles}{addition \ of\ the\ total\ volume}[/tex]
[tex]Molarity \ of \ C_5H_5N^+H = \dfrac{0.0750 \ M \times 2.65 \ L}{2.65 \ L + 0.48833 \ L}[/tex]
[tex]Molarity \ of \ C_5H_5N^+H = \dfrac{0.19875 \ ML}{3.13833 L }[/tex]
[tex]= \ 0.06333\ M[/tex]
Now, the next step is to draw out the I.C.E table.
[tex]C_5H_5N^+H + H_2O[/tex] ⇄ [tex]C_5H_5N + H_3O^+[/tex]
I 0.06333 0 0
C - x x x
E 0.06333 -x x x
[tex]K_a = \dfrac{10^{-14}}{1.7 \times 10^{-19}} \\ \\ K_a = 5.8824 \times 10^{-6}[/tex]
[tex]K_a = \dfrac{[C_5H_5N][H_3O^+] }{[C_5H_5N^+H] } \\ \\ 5.8824 \times 10^{-6} = \dfrac{x^2}{0.06333 - x}[/tex]
Assuming x < 0.06333
[tex]x^2 = 5.8824 \times 10^{-6} \times 0.06333[/tex]
Then
[tex]x^2 = 3.72532392 \times 10^{-7} \\ \\ x= \sqrt{3.72532392 \times 10^{-7}} \\ \\ x = 6.1035 \times 10^{-4} \ M[/tex]
[tex][H_3O^+] = x = 6.1035 \times 10^{-4} \ M \\ \\ pH = -log (6.1035 \times 10^{-4}) \\ \\ \mathbf{\\ pH = 3.215}[/tex]
The pH for HNO3 needed to reach the equivalence point in the titration of 2.65 L of 0.0750 M pyridine (C5H5N, Kb = 1.7 × 10−9) is
HNO3 + C5H5N→CSH5NH + + NO3
Moles of C5H5N = volume x concentration
=2.65 x 0.0750
=0.1987 mol
Moles of HNO3 needed = moles of C5H5N = 0.19875 mol Volume of HNO3 eeded = moles / con
=0.19875/0.54
=0.363L
=363 mL
At the equivalence point, most effective C5H5NH + a NO3-are Moles of C5H5NH+ = moles of C5H5N = 0.19875 mol
Total extent of answer n = 2.65 + 0.363 =3.013 L
Initial concentration [ C5H5NH + ] o = moles/ volume =0.19875/3.013 =0.06596 M
Kb of C5H5N = 1.7 x 10 ^ 9
By fixing the equation,
H + = 6.199 * 10 ^ 4 M
pH=-log[H+]
=3.207
=3.21 pH
What is pH ?
The pH is the degree of ways acidic or simple a substance is. In humans, pH stability performs a position in preserving the frame functioning optimally. The best pH of the frame is barely alkaline, which helps sure biochemical reactions like oxygenating the blood.
Thus it is clear above.
To learn more aboyt the titration refer to link :
https://brainly.com/question/186765
