Respuesta :
Answer: The pH of the solution in the flask after the chemist has added 231.4 mL of NaOH solution to it is 12.018.
Explanation:
The given data is as follows.
Molarity of NaOH = 0.32 M
Molarity of [tex]HC_{3}H_{7}CO_{2}[/tex] = 0.32 M,
Volume of [tex]HC_{3}H_{7}CO_{2}[/tex] = 216.8 ml = 0.2168 L (as 1 L = 1000 mL)
Volume of NaOH = 231.4 ml = 0.2314 L
Therefore, number of moles of [tex]HC_{3}H_{7}CO_{2}[/tex] is as follows.
No. of moles = Molarity × Volume
= [tex]0.32 \times 0.2168[/tex]
= 0.069 moles
Now, number of moles of NaOH will be calculated as follows.
No. of moles = Molarity × Volume
= [tex]0.32 \times 0.2314[/tex]
= 0.074 moles
Chemical equation for this reaction is as follows.
[tex]HC_{3}H_{7}CO_{2} + NaOH \rightarrow NaC_{3}H_{7}CO_{2} + H_{2}O[/tex]
Initial: 0.069 0.074
Change: -0.069 -0.069
Equilibm: 0 0.004672
Total volume will be as follows.
0.2168 + 0.2314 = 0.4482 L
Here, the concentration of NaOH is equal to the concentration of hydroxide ions.
So, [NaOH] = [tex][OH^{-}] = \frac{n}{V}[/tex]
= [tex]\frac{0.004672}{0.4482}[/tex]
= 0.010424 M
We know that,
pOH = [tex]-log [OH^{-}][/tex]
= -log (0.010424)
= 1.928
Hence, the pH will be calculated as follows.
pH = 14 - pOH
= 14 - 1.982
= 12.018
Thus, we can conclude that the pH of the solution in the flask after the chemist has added 231.4 mL of NaOH solution to it is 12.018.
