The ionisation constant of NH3 is k=1.8*10^-5. Calculate K for its conjugate acid NH^4

Answer 1

The ionization constant, Ka, of NH3 can be expressed as follows:

Ka = [NH4+][OH-] / [NH3]

The ionization constant Kb can be calculated using the following relationship:

Kb = Kw / Ka

Where Kw is the ionization constant of water, which is equal to 1.0 x 10^(-14) at 25°C.

We are given Kb for NH3:

Kb(NH3) = 1.8 * 10^(-5)

We want to calculate Ka for its conjugate acid, NH4+.

Ka(NH4+) = Kw / Kb

Ka(NH4+) = (1.0 * 10^(-14)) / (1.8 * 10^(-5))

Ka(NH4+) = 5.56 * 10^(-10)

So, the ionization constant, Ka, for the conjugate acid NH4+ is approximately 5.56 * 10^(-10).