Buffer Solution Calculator, Formula and Sample Problems

Buffer Solution Calculator :

Enter the Buffer solution calculator the Acid concentration in molars(M), Salt concentration in molars(M), and you get the calculation below the calculator check it.

Buffer pH Calculator

Buffer Solution Formula :

Buff solution formula is PH is equal to the pka  and addition the log of multiply the salat in log[salt] divided by the [Acid].Hence Buff Solution formula can be written as,

PH=pka+log[salt]/[Acid]

The pH of any acidic buffer solution is always less than 7 and the pH of any basic buffer solution is always greater than 7.

Sample Problems :

Example 1 :

Calculate the ratio of concentrations of formation and formic acid in a buffer solution so that its pH is required to be 3? Identify the pH of this buffer to have the maximum buffer capacity? Ka of formic acid is 2.8 *10-4.

Solution :

We have the equation

PH=pka+log[salt]/[Acid]

3=-log(2.8*10-4)+log[formate]/[formic acid]

3=3.55+log[formate]/[formic acid]

Log[formate]/[formic acid]=3-3.55=0.55

[formate]/[formic acid]=2.8

The buffer capacity would be maximul near the pka of the acid for maximum buffer capacity

PH=pka=-log ka

=-log(2.8*10-4)

=3.55

Buffer capacity =3.55

Example 2 :

Calculate the volume of 0.4M solution of acetic acid that needs to be added to 200 ml of 0.4M solution of sodium acetate to obtain a buffer solution of pH 6.00. pKa of acetic acid is 5.74.

Solution :

We have the equation

PH= pka+log[salt]/[Acid]

Log[salt]/[Acid]=PH-Pka

=6-5.74=0.26

[salt]/[Acid]=2.8

Number of moles of sodium acetate

=200*0.4/1000

=0.08mol

Let volume of 0.4M acetic acid added =VmL

Number of moles of acetic acid=V*0.4/1000

0.04/V*0.4/1000=0.16

Therefore

V=0.04*1000/0.4*0.16

V=16mL of acetic acid is added

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