Ethiopia Grade 12 Chemistry Unit 1: Solutions Question Answers

Ethiopia Grade 12 Chemistry Unit 1: Solutions Question Answers:  Text Book Practice the sample multiple-choice question for the Grade 12 Chemistry Entrance examination.

Ethiopia Grade 12 Chemistry

Unit 1: Solutions

1. What is the meaning of Mg(OH)₂ 

• A) Milk of Magnesia
• B) Magnesium
• C) Hydroxide
• D) All of the above

Answers: A) Milk of Magnesia Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)₂. It occurs in nature as the mineral brucite.

2. A colloid consists of two parts

• A) True
• B) False

Answers: A) True: A colloid is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance.

3. Which is an example of a colloid?

• A) Milk,
• B) Jelly,
• C) Muddy water,
• D) All of the above

Answers: D) All of the above

4. The light beam can pass through the colloidal mixture.

• A) True
• B) False

Answers: A) True

5. Which is an example of a gas?

• A) Air,
• B) Water,
• C) Muddy water,
• D) Alcoholic beverage

Answers: A) Air

6. Which is an example of a liquid?

• A) Acetone
• B) Water,
• C) Ethanol
• D) All of the above

Answers: D) All of the above

7. Match the following

Solutions	Example
A) gas-gas	I) Coca-cola
B)liquid-liquid	II) Air
C) Gas-liquid	III) alloys
D) Solid-liquid	IV) Water
E)solid-solid	V) Saltwater

Answers:

• A) : II)
• B) : IV)
• C) : I)
• D): V)
• E) : III)

8) Ethanol mixed with water but old does not. Why?

• A) Because both are Miscible liquids
• B) Because of prominent solvent
• C) Because of  like dissolves like
• D) Because of  dislike dissolves like

Answers: C. “Like dissolves like” is an expression used by chemists. It refers to “polar” and “nonpolar” solvents and solutes. Basic example: Water is polar. Oil is non-polar. Water will not dissolve oil.

09. Which of the following is NOT an immiscible liquids

• A) Oil and Water
• B) Pentane and Acetic Acid
• C) Benzene and Carbon tetrachloride
• D) All of the above

Answers: C) Benzene (C₆H₆ ) and Carbon tetrachloride (CCl₄) these two liquids are said to be miscible

10.) London forces refer to

• A) Acting between atoms and molecules
• B) It is a temporary attractive force
• C) its the is the weakest intermolecular force.
• D) All of the above

Answers: D) The LDF (London Dispersion Force) is named after the German-American physicist Fritz London.

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*Answers are highlighted in bold and green

Exercise 1.2

1. A solution is a:

• A) heterogeneous mixture
• B) homogeneous 
• C) Suspension
• D) colloid

2.  Soda water is an example of:

• A) liquid-liquid
• B) solid-liquid solution
• C) gzs-liquid solution
• D) gas-gas solution

3. Which of the following substances are not readily miscible within each Other’?

• A) C₆H₆ and CCl₄
• B) C₂H₅OH and CCl₄
• C) C₂H₅OH and H₂O
• D) CH₃OH and H₂O

4. Rate of dissolution is largely dependent upon

• A) the inter-particle forces
• B) the Surface area of Solid Solute
• C) the temperature of the system
• D) the pressure of the system

5. the quantitative relationship between gas solubility and pressure is given by:

• A) Raoult’s law
• B) Henry’s law
• C) Hess’s law
• D) Dalton’s law

6. When a non-volatile solute is added to a pure solvent the:

• A) vapour pressure Ofthe Solvent decreases.
• B) vapour pressure Ofthe solvent increases.
• C) boiling point Ofthe Solution decreases.
• D) freezing point of the solution increases.

7. Which of the following is not true about ideal solutions?

• A) the volume of an ideal solution is the sum Of the volume Ofits pure components
• B) there is no expansion or contraction on mixing
• C) the heat of solutiion is zero
• D) they deviate Raoult’s law

8. The ratio of the number of moles of solute divided by the total number of moles gives:

• the mole fraction of the solute
• the molarity of the solution
• the molality of the solution
• the normality of the solution

9. Which of the following liquid pairs shows a positive deviation from Raoult’s law?

• octane, chloroform
• ethanol, water
• benzene, methanol
• water, nitric acid

11. Which of the following is not a colligative property?

• Osmotic pressure
• Vapour pressure
• Boiling point elevation
• Freezing point depression

12. The addition of a non-volatile solute to a solvent results in the lowering of:

• boiling point as well as freezing point
• freezing point as well as vapour pressure
• vapour pressure as well as density
• boiling point as well as vapour pressure

13. Phosphoric acid reacts with calcium hydroxide to form calcium hydrogen phosphate and water. The equivalent mass of phosphoric acid in this reaction will be:

•  98 g/eq
•  32.6 g/eq
•  49 g/eq
•  14 g/eq

14. A non-volatile electrolyte dissolved in an aqueous solution with the same molal proportion as a nonelectrolyte produces:

• the same colligative effect
• lower colligative effect
• higher colligative effect
• no colligative effect

15. According to Raoult’s law, the relative lowering of vapour pressure of a solution by a non-volatile solute is:

• equal to the mole fraction of solvent
• equal to the mole fraction of solute
• directly proportional to mole fraction of solute
• equal to normality of solution