Chemistry 9th Chap 10 : Topic 5 - Maryam Publications

Chemistry Chapter 10 : Topic 5

Bases and Alkalis

1 / 20

Which statement correctly defines a base?

A) An oxide or hydroxide of a metal that can neutralize acids.

B) A compound that must be soluble in water to act as a base.

C) A substance that always dissolves in water to form acids.

D) A substance that reacts with metals to produce hydrogen gas only.

2 / 20

Which of the following best distinguishes an alkali from a base?

A) Alkalis are always metal oxides while bases are hydroxides.

B) Alkalis are water-soluble bases, while bases may or may not be soluble in water.

C) Alkalis are only found in liquid state.

D) Alkalis do not react with acids, while bases do.

3 / 20

Which of the following is NOT an alkali?

A) CuO

B) Ca(OH)₂

C) KOH

D) NaOH

4 / 20

Why is sodium hydroxide classified as an alkali?

A) It is a metal oxide.

B) It is a gas at room temperature.

C) It dissolves in water and produces OH⁻ ions.

D) It reacts only with non-metals.

5 / 20

Which statement is correct about all alkalis?

A) All alkalis are acids in disguise.

B) All alkalis are insoluble in water.

C) All alkalis are metal oxides.

D) All alkalis are bases, but not all bases are alkalis.

6 / 20

Which of the following is a base but NOT an alkali?

A) NH₄OH

B) KOH

C) CuO

D) NaOH

7 / 20

What happens when calcium oxide reacts with water?

A) It forms Ca(OH)₂ which acts as an alkali.

B) It forms salt and water.

C) It remains unchanged.

D) It forms an acid.

8 / 20

Which of the following best describes ammonia in water?

A) Weak alkali

B) Insoluble base

C) Strong acid

D) Metal oxide

9 / 20

Why is magnesium hydroxide considered a weak alkali?

A) It is a metal oxide.

B) It is completely insoluble in water.

C) It is highly soluble in water.

D) It is slightly soluble in water.

10 / 20

Which pair correctly represents both bases?

A) HCl and H₂SO₄

B) CuO and MgO

C) CO₂ and SO₂

D) NaCl and KCl

11 / 20

Which of the following is TRUE about metal oxides?

A) All metal oxides are acids.

B) Metal oxides are always soluble in water.

C) Many metal oxides act as bases.

D) Metal oxides do not react with acids.

12 / 20

Which of the following is a correct characteristic of alkalis?

A) They never react with acids.

B) They are all insoluble metal oxides.

C) They are soluble bases producing OH⁻ ions in water.

D) They are always gases.

13 / 20

Which substance will increase OH⁻ concentration in water?

A) SO₂

B) HCl

C) NaOH

D) CO₂

14 / 20

Which base is least likely to be classified as an alkali?

A) Ca(OH)₂

B) Fe₂O₃

C) NaOH

D) KOH

15 / 20

What is the key requirement for a base to be called an alkali?

A) It must be acidic in nature.

B) It must contain carbon.

C) It must be a gas.

D) It must be soluble in water.

16 / 20

Which of the following correctly shows a base that is NOT an alkali?

A) CuO

B) NaOH

C) KOH

D) Ca(OH)₂

17 / 20

Why is potassium hydroxide classified as an alkali?

A) It produces OH⁻ ions in aqueous solution.

B) It is a metal oxide.

C) It is insoluble in water.

D) It reacts only with metals.

18 / 20

Which statement about bases and alkalis is correct?

A) Alkalis do not neutralize acids.

B) Alkalis are a special type of base.

C) No base is soluble in water.

D) All bases are alkalis.

19 / 20

Which of the following best represents an insoluble base?

A) NH₄OH

B) KOH

C) CuO

D) NaOH

20 / 20

What is the correct relationship between bases and alkalis?

A) Alkalis are a type of base that is soluble in water.

B) Bases are a type of alkali.

C) All bases are soluble.

D) Alkalis are broader than bases.

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