Question

Calculate the dissociation constant of formic acid when it is 4.5% dissociated in a 0.1N solution
at 298 K?​

Answer 1

Answer:

2.1×10

−4

When formic acid is dissolved in water, it partially dissociates (4.5%).

K

a

=

C(1−α)

Cα×Cα

We assume α∼0⇒1−α∼1

⇒K

a

=

1

Cα

2

=0.1×0.045×0.045=2.02×10

−4