The of the methylammonium ion ( ) at is

CHEMISTRY · Multi-part · AP · Chemistry · Acids and Bases · Acids and Bases

Problem

The

pK_a

of the methylammonium ion (

CH_3NH_3^+

) at

25\,^{\circ}\text{C}

10.64

. A student prepares

40.0\,\text{mL}

of a

0.0500\,\text{M}

aqueous solution of methylamine (

CH_3NH_2

) at the same temperature. The auto-ionization constant of water is

K_w = 1.0 \times 10^{-14}

. Answer the following questions. (1) Part 1: Determine the base dissociation constant,

K_b

, for methylamine at

25\,^{\circ}\text{C}

. (2) Part 2: Calculate the percent ionization of methylamine in the

0.0500\,\text{M}

solution prepared by the student.