Respuesta :
3-(n-morpholino)propanesulfonic acid [MOPS] is used as a buffer specially in biological systems
When we add NaOH to it , it forms salt with it and there is a change in the pH of the solution
MOPS + NaOH ---> NaMOPS + H₂O
The Hendersen equation for estimation of pH of a buffer is
pH = pKa + log[salt]/[acid]
7.55 = 7.18 + log[salt]/[acid]
On solving
[salt] / [acid] = 2.344
moles of salt required = 2.344 X moles of acid
initial moles of acid present = 389 X 0.0543 = 21.12 mmoles
let the moles of base added = x mmol
As per equation each mole of base will react with one mole of MOPS
Therefore
moles of salt formed = x mmol
moles of acid left = 21.12-x
x = 2.344 (21.12-x)
x = 49.51 - 2.344x
x = 14.80 mmol
this is the millimoles of base required
So the volume of NaOH needed (mL) = moles / molarity = 14.80/0.170 = 87.05 mL
Based on the data provided, 87.05 mL of NaOH is required to give the solution a pH of 7.55.
What is the equation of the reaction of MOPS and NaOH?
The equation of the reaction of MOPS and NaOH is given below as follows:
- MOPS + NaOH ---> NaMOPS + H₂O
The volume of NaOH required is determined using the Henderson-Hasselbalch equation given as follows:
- pH = pKa + log[salt]/[acid]
From the dat given:
7.55 = 7.18 + log[salt]/[acid]
[salt] / [acid] = 2.344
moles of salt = 2.344 × moles of acid
Initial moles of acid present = 389 mL × 0.0543 M = 21.12 mmoles
Assuming the moles of base added = x mmol
From the equation of the reaction, 1 mole of MOPS will react with 1 mole of KOH to produce 1 mole of salt
Therefore;
moles of salt formed = x mmol
moles of acid left = 21.12 - x
x = 2.344 (21.12 - x)
x = 49.51 - 2.344x
x = 14.80 mmol
Thus, 14.80 millimoles of base is required
Then;
Volume of NaOH needed (mL) = 14.80 mmol/0.170 M
Volume of NaOH required = = 87.05 mL
Therefore, 87.05 mL of NaOH is required to give the solution a pH of 7.55.
Learn more about pH and pKa at: https://brainly.com/question/22390063
