Aqueous Solution

Aqueous Solution

Dissociation

• The separation of ions that occurs when an ionic compound dissolves

• 
  

               H2O

  NaCl(s) →        Na+ (aq) + Cl- (aq)

  
  

• 
  

               H2O

  CaCl2(s) ------> Ca2+ (aq) + 2Cl- (aq)

Dissociation Problem

Write the equation for the dissolution of aluminium sulfate, Al2(SO4)3, in water. How many moles of aluminum ions and sulfate ions are produced by dissolving 1 mol of aluminum sulfate? What is the total number of moles of ions produced by dissolving 1 mol of aluminum sulfate?

Solubility

No ionic compounds are completely insoluble but some are near insoluble, and are therefore considered to be insoluble. We have a few rules.

Rule 1

Sodium, Potassium, and ammonium compounds are soluble in water

Multiple Choice

Would ammonium chloride be soluble in water?

• Yes

• No

Rule 2

Nitrates, Acetates, and chlorates are soluble

Multiple Choice

Would magnesium chlorate be soluble?

• Yes

• No

Rule 3

Most chlorides are soluble, except silver, mercury(I), and lead.Lead(II) chloride is soluble in hot water.

Multiple Choice

Would lead(II) chloride be soluble in 20 C water?

• Yes

• No

Multiple Choice

Is Mercury(I) chloride soluble?

• Yes

• No

Rule 4

Most sulfates are soluble, except those of barium, strontium, lead, calcium, and mercury(1).

Multiple Choice

Is sodium sulfate soluble?

• Yes

• No

Rule 5

Most carbonates, phosphates, and silicates are insoluble, except those of sodium, potassium,and ammonium.

Multiple Choice

Is sodium carbonate soluble?

• Yes

• No

Rule 6

Most sulfides are insoluble, except those of calcium, strontium, sodium, potassium, and ammonium

Multiple Choice

Is Lithium sulfide soluble?

• Yes

• No