Solubility Practice Questions
WAEC (West Africa) · WAEC Chemistry · 150 free MCQs with instant results and detailed explanations.
150
Total
46
Easy
75
Medium
29
Hard
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Sample Questions from Solubility
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Q1
Easy
Which of the following factors does NOT affect the solubility of a substance in a solvent?
A.
Temperature of the solvent
B.
Pressure above the solvent
C.
Nature of the solute
D.
Color of the solute
Show Answer & Explanation
Correct Answer: D
The color of the solute does not influence its solubility in a solvent. Solubility is primarily affected by temperature, pressure, and the chemical nature of both solute and solvent.
Q2
Easy
If 50 grams of salt is dissolved in 1000 mL of water at room temperature, what is the solubility of the salt in water in grams per liter?
A.
25 g/L
B.
50 g/L
C.
100 g/L
D.
200 g/L
Show Answer & Explanation
Correct Answer: B
To find the solubility in g/L, we divide the mass of salt by the volume of solution in liters. 50 grams of salt in 1 liter of water gives a solubility of 50 g/L.
Q3
Easy
Which of the following statements is true about saturated solutions?
A.
They can dissolve more solute at any temperature.
B.
They contain the maximum amount of solute at that temperature.
C.
They are always at boiling point.
D.
They do not exist for all solutes.
Show Answer & Explanation
Correct Answer: B
A saturated solution is one that has reached its maximum solubility at a specific temperature, meaning no more solute can be dissolved under those conditions.
Q4
Medium
Which of the following substances is most soluble in water at room temperature?
A.
Sodium chloride (NaCl)
B.
Calcium carbonate (CaCO3)
C.
Silver bromide (AgBr)
D.
Barium sulfate (BaSO4)
Show Answer & Explanation
Correct Answer: A
Sodium chloride (NaCl) is highly soluble in water due to its ionic nature, allowing it to dissociate completely in solution, while the other compounds listed have lower solubility.
Q5
Medium
What effect does temperature generally have on the solubility of solids in liquids?
A.
Solubility decreases with temperature.
B.
Solubility is unaffected by temperature.
C.
Solubility increases with temperature.
D.
Solubility fluctuates randomly with temperature.
Show Answer & Explanation
Correct Answer: C
Generally, the solubility of most solid solutes increases as the temperature of the solvent increases, allowing more solute to dissolve.
Q6
Medium
A student dissolves 10 grams of potassium nitrate (KNO3) in 100 mL of water at 20°C. If the solution is saturated at this temperature, how much more KNO3 can be added to the solution?
A.
0 grams
B.
5 grams
C.
10 grams
D.
15 grams
Show Answer & Explanation
Correct Answer: A
If the solution is already saturated with 10 grams of KNO3, no additional KNO3 can dissolve in the solution, thus 0 grams can be added.
Q7
Medium
Which of the following is an example of a gas that is soluble in water?
A.
Oxygen (O2)
B.
Nitrogen (N2)
C.
Carbon dioxide (CO2)
D.
Helium (He)
Show Answer & Explanation
Correct Answer: C
Carbon dioxide (CO2) is soluble in water, forming carbonic acid, while the other gases listed have very low solubility in water.
Q8
Hard
A saturated solution of sodium chloride at 25 °C can hold a maximum of 36 grams of sodium chloride in 100 grams of water. If you have 200 grams of water, what is the maximum amount of sodium chloride that can be dissolved at this temperature?
A.
72 grams
B.
36 grams
C.
100 grams
D.
50 grams
Show Answer & Explanation
Correct Answer: A
In 100 grams of water, a maximum of 36 grams of NaCl can dissolve. Therefore, in 200 grams of water, it can hold double the amount, which is 72 grams.
Q9
Hard
If the solubility product (Ksp) of lead(II) chloride (PbCl2) is 1.6 × 10^-5 at a certain temperature, what is the concentration of Pb²⁺ ions in a saturated solution of lead(II) chloride assuming complete dissociation?
A.
0.04 mol/L
B.
0.02 mol/L
C.
0.08 mol/L
D.
0.01 mol/L
Show Answer & Explanation
Correct Answer: B
The solubility product expression for PbCl2 is Ksp = [Pb²⁺] × [Cl⁻]². If 's' is the solubility of PbCl2, then [Pb²⁺] = s and [Cl⁻] = 2s. Thus, Ksp = s × (2s)² = 4s³. Setting 4s³ = 1.6 × 10^-5 and solving gives s = 0.02 mol/L.
Q10
Hard
Which of the following salts is least soluble in water at room temperature?
A.
Barium sulfate (BaSO4)
B.
Sodium chloride (NaCl)
C.
Potassium nitrate (KNO3)
D.
Calcium chloride (CaCl2)
Show Answer & Explanation
Correct Answer: A
Barium sulfate (BaSO4) has very low solubility in water due to its strong ionic bonds and the small size of the barium ion, making it the least soluble among the given options. In contrast, sodium chloride, potassium nitrate, and calcium chloride are more soluble in water.
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Solubility — WAEC (West Africa) WAEC Chemistry Practice Questions Online
This page contains 150 practice MCQs for the chapter Solubility in WAEC (West Africa) WAEC Chemistry. The questions are organized by difficulty — 46 easy, 75 medium, 29 hard — so you can choose the right level for your preparation.
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