Question

Calculate the molar solubility of Sn(OH)₂ in a buffer solution containing equal concentrations of NH₃

a) 0.005 M
b) 0.010 M
c) 0.015 M
d) 0.020 M

Answer 1

To calculate the molar solubility of Sn(OH)2 in a buffer solution containing equal concentrations of NH3 and NH4+, we can use the Henderson-Hasselbalch equation and the solubility product constant (Ksp) expression.

Step-by-step explanation:

To calculate the molar solubility of Sn(OH)2 in a buffer solution containing equal concentrations of NH3 and NH4+, we need to consider the ionic equation for the dissolution of Sn(OH)2 in water:

Sn(OH)2(s) ⇌ Sn2+(aq) + 2OH-(aq)

Since both NH3 and NH4+ are present in equal concentrations, we can use the Henderson-Hasselbalch equation to calculate the concentration of OH-:

pOH = pKa + log([A-]/[HA])

where [A-] is the concentration of the conjugate base (NH4+) and [HA] is the concentration of the acid (NH3). In this case, the pKa is the pKb of NH4+ (which can be calculated from the Kb of NH3).

Once we have the pOH, we can use the relation pOH = -log[OH-] to calculate the concentration of OH-. Finally, we can use the concentration of OH- to calculate the molar solubility of Sn(OH)2 using the solubility product constant (Ksp) expression:

Ksp = [Sn2+][OH-]²

By substituting the calculated concentration of OH- into the Ksp expression, we can solve for [Sn2+]. This will give us the molar solubility of Sn(OH)2 in the buffer solution.