Methylamine, CH3NH2, is a weak base and one of several substances that give herring brine its pungent odor. In .100 M CH3NH2, only 6.4 percent of the base has undergone ionization. What are Kb and pKb of methylamine

Respuesta :

Answer:

[tex]K_{b}[/tex] is 0.000438 and [tex]pK_{b}[/tex] is 3.36

Explanation:

Methylamine is a monoprotic base.

For a monoprotic base, [tex]K_{b}=\frac{ca^{2}}{(1-a)}[/tex]

where, c is concentration of base in molarity and a is it's degree ionization

Here [tex]a=\frac{6.4}{100}=0.064[/tex] and c = 0.100 M

So, [tex]K_{b}=\frac{(0.100)\times (0.064)^{2}}{(1-0.064)}=0.000438[/tex]

We know, [tex]pK_{b}=-logK_{b}[/tex]

Hence, [tex]pK_{b}=-log(0.000438)=3.36[/tex]