How many milliliter of 0.1m naoh should be added to 50.0 ml of 0.1m formic acid hcooh (ka=1.8*10^-4), to obtain a buffer with a ph of 4.0?

The volume of NaOH that must be added is 32.3 mL

Explanation:

Let us assume that volume of NaOH required is 'V' mL

To calculate the millimoles of NaOH, we use the equation:

Molarity of NaOH solution = 0.1 M

Volume of solution = V mL

Putting values in above equation, we get:

Molarity of HCOOH solution = 0.1 M

Volume of solution = 50 mL

Putting values in above equation, we get:

The chemical equation for the reaction of formic acid and sodium hydroxide follows:

Initial:                    5           0.1V

Final:              5 - 0.1 V        -                    0.1V         -

where,

= acid dissociation constant =

Putting values in above equation, we get:

We are given:

[HCOONa] = 0.1V

[HCOOH] = 5 - 0.1V

pH = 4.0

Putting values in above equation, we get:

Hence, the volume of NaOH that must be added is 32.3 mL

the answer is 1 i believe

b) nuclear ive learned that in a pedtrodic table