A solution is prepared at 25 C that is initially 029 M in di

A solution is prepared at 25 °C that is initially 0.29 M in dimethylamine (CH) 2NH), a weak base with K,-54-1 chloride ((CH,),NH2CI). Calculate the pH of the solution. Round your answer to 2 decimal places. 0- , and 0.27 Min dimethylammonium PH

Solution

pKb = -log Kb

pKb = -log (5.4 x 10-4)

pKb = 3.2676

now

according to hasselbalch hendersen equation

pOH = pKb + log [conjugate acid/base]

pOH = pKb + log [(CH3)2NH2Cl / (CH3)2NH]

pOH = 3.2676 + log [0.27 / 0.29]

pOH = 3.2366

now

pH + pOH = 14

pH = 14 - pOH

pH = 14 - 3.2366

pH = 10.7634