Question

you are given mixtures containin gthe following compounds. Which compound in each pair could be separated by stirring the solid mixture with water? (A) NaOH and Ca(OH)2 (B) MgCl2 and MgF2 (C) Agl and KI (D) NH4Cl and PbCl2

Answer 1

Answer:

(A) NaOH and Ca(OH)2: Ca(OH)2

(B) MgCl2 and MgF2: MgF2

(C) Agl and KI: AgI

(D) NH4Cl and PbCl2: PbCl2

Explanation:

We need to see the solubility in water, at similar temperatures, for each compound and see which one is less soluble than the other:

NaOH: 1000 g/L (25 °C)

Ca(OH)2: 1.73 g/L (20 °C)

MgCl2: 54.3 g/100 mL (20 °C)

MgF2: 0.013 g/100 mL (20 °C)

Agl: 3×10−7g/100mL (20 °C)

KI: 140 g/100mL (20 °C)

NH4Cl: 383.0 g/L (25 °C)

PbCl2: 10.8 g/L (20 °C)

After the comparison made we can conclude that the less soluble, after saturation of water, will precipitate first.