Question

The acid-dissociation constant, ka, for gallic acid is 4.57 ⋅ 10-3. what is the base-dissociation constant, kb, for the gallate ion? the acid-dissociation constant, ka, for gallic acid is 4.57 10-3. what is the base-dissociation constant, kb, for the gallate ion? 2.19 ⋅ 10-12 2.19 ⋅ 102 5.43 ⋅ 10-5 4.57 ⋅ 10-3 7.81 ⋅ 10-6

Answer 1

Answer: The base dissociation constant for a conjugate base is
`2.18* 10^(-12)`

Step-by-step explanation:

To calculate the base dissociation constant for the given acid dissociation constant, we use the equation:

`K_w=K_b* K_a`

where,

`K_w` = Ionic product of water =
`10^(-14)`

`K_a` = Acid dissociation constant =
`4.57* 10^(-3)`

`K_b` Base dissociation constant = ?

Putting values in above equation, we get:

`10^(-14)=4.57* 10^(-3)* K_b\\\\K_b=2.18* 10^(-12)`

Hence, the base dissociation constant for a conjugate base is
`2.18* 10^(-12)`

Answer 2

Hello!

To determine the Kb of gallic acid is actually very simple.

The dissociation reaction of Gallic Acid (HGal) is the following:

HGal+H₂O ⇄ H₃O⁺ + Gal⁻

The equation for converting from Ka to Kb is the following:


`Ka*Kb=Kw \\ \\ Kb= (Kw)/(Ka)= (1*10^(-14) )/(4,57*10^(-3) )=2,19 * 10^(-12)`

So, the Kb is 2,19*10⁻¹²

Have a nice day!