aplinglearningcomibiscmsmodibisviewphpid494 7347 arning 3820

aplinglearning.com/ibiscms/mod/ibis/view.php?id=494 7347 arning 3/8/2018 11:59 PM O 21.2/25 Table Question 24 of 35 62 Sapling Learning If the K of a weak base is 5.4 106, what is the pH of a 0.31 M solution of this base?

Solution

BOH + H2O <===> BH2O^+ (aq) + OH^- (aq)

0.31 M. x. x

Kb = x^2 / 0.31 => 5.4*10^-6

x = 1.29*10^-3 M => [OH^-]

pOH = - log (1.29*10^-3) => 2.89

pH = 14 - 2.89 => 11.11

pH = 11.11