# Problem: A solution of 0.23 mol of the chloride salt of protonated quinine (QH+), a weak organic base, in 1.0 L of solution has pH=4.58.Find the Kb of quinine (Q).

###### FREE Expert Solution

We are being asked to calculate the Kb of quinine (Q)

Quinine chloride salt dissociates into:

QHCl(aq) + H2O(l)→QH+(aq) + Cl-(aq)

Since we’re dealing with a weak acid and Ka is an equilibrium expression, we will have to create an ICE chart to determine the equilibrium concentration of each species:

QH+weak acidproton donor
H2O→ will act as the weak baseproton acceptor

Equilibrium reaction:        QH+(aq) + H2O(l)  Q(aq) + H3O+(aq)

We are given 0.23 mole of quinine chloride in 1.0 L solution hence:

Molarity of QH+ = 0.23 M

97% (85 ratings) ###### Problem Details

A solution of 0.23 mol of the chloride salt of protonated quinine (QH+), a weak organic base, in 1.0 L of solution has pH=4.58.

Find the Kb of quinine (Q).

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