## Calculate the percent ionization of ha in a 0.10 m solution.

### Question:

Calculate the percent ionization of ha in a 0.10 m solution.

### Answer & Explanation:

*Question:*

A certain weak acid, HA, has a Ka value of 1.1 * 10-7.

*Part A*

Calculate the percent ionization of HA in a 0.10 M solution.

**Part B**

Calculate the percent ionization of HA in a 0.010 M solution.

Calculating the Degree of Dissociation of Weak Acids

Consider a weak monoprotic acid of the form HA . Let its concentration be c and dissociation constant be KaConsider a weak monoprotic acid of the form HA . Let its concentration be c and dissociation constant be Ka

The general chemical equation depicting the ionization of HA is :

HA ⇋ H + A−

c(1−α) cα cα

α is the degree of dissociation of the acidα is the degree of dissociation of the acid

∴Ka=[H+][OH−]/[HA]

⇒Ka=(cα)(cα)/c(1−α)

⇒Ka=cα2/1−α (1)

⇒cα2+αKa−Ka=0

Hence, the degree of dissociation can be evaluated by solving the above quadratic equation.

When the dissociation constant Ka has a very small value, we can use approximations in equation (1) to find the degree of dissociation.

1−α≈1

⇒Ka=cα2

⇒α=√Kac

Answer and Explanation:

(a)Ka=1.1×10−7

c=0.1 M

∴α=√Ka/c

⇒α=√1.1×10−7/0.1

⇒α=1.048×10−3=0.1048%

(b)Ka=1.1×10−7

c=0.01 M

∴α=√Ka/c

⇒α=√1.1×10−7/0.01

⇒α=3.316×10−3=0.3136%

## Answer ( 1 )

Answer Above.