Acids Bases and Salts Quiz

Which of the following statements are correct regarding the reaction of acids with metals? 1. Acids react with all metals to produce hydrogen gas. 2. The reaction between acids and copper produces copper chloride and hydrogen. 3. Magnesium reacts rapidly with dilute hydrochloric acid, releasing hydrogen.

1. 1 and 2 only
2. 1 and 3 only
3. 2 and 3 only
4. 1, 2, and 3

Answer: (c) 2 and 3 only

Which pair of substances will both turn methyl orange yellow?

1. Vinegar and Ammonia
2. Lime water and Sodium hydroxide
3. Lemon juice and lime water
4. Carbonated drink and Vinegar

Answer: (b) Lime water and Sodium hydroxide

Which region (X, Y, or Z) would an antacid tablet target, and why?

1. X, to neutralise bases in the stomach
2. Z, to enhance acidic strength
3. Y, to maintain the stomach's acidity
4. X, to neutralise excess stomach acid

Answer: (d) X, to neutralise excess stomach acid

A white precipitate forms when sodium hydroxide is added to a colourless solution of zinc nitrate. On adding excess sodium hydroxide, the precipitate dissolves. What can be concluded about zinc hydroxide?

1. It is soluble in water and forms a basic solution
2. It is not soluble at first but may dissolve in more sodium hydroxide
3. It is an acidic salt that forms a neutral solution
4. It is a strong base and completely dissociates

Answer: (b) It is not soluble at first but may dissolve in more sodium hydroxide

A student adds calcium hydroxide to sulfuric acid until no more reaction occurs. What remains in the beaker after evaporation?

1. Water and calcium hydroxide
2. Sulphur dioxide and water
3. Calcium sulphate
4. Calcium oxide

Answer: (c) Calcium sulphate

Read the statement and choose true and false: 1. A salt is always neutral in nature. 2. The pH of a neutral salt solution is always exactly 7. 3. All salts are formed from neutralisation reactions.

1. A- T, B- T, C- T
2. A- T, B- T, C- F
3. A- T, B- F, C- F
4. A- F, B- F, C- F

Answer: (d) A- F, B- F, C- F

Read the statement and correctly fill the blanks: 1. Blue litmus paper turns ______ when dipped in an acidic solution. 2. When sulphuric acid reacts with zinc, ______ gas is evolved. 3. The acid present in vinegar is ______ acid.

1. A-red, B- hydrogen, C- acetic
2. A- pink, B- oxygen, C- citric
3. A- green, B- carbon dioxide, C- tartaric
4. A- yellow, B- nitrogen, C- carbonic

Answer: (a) A-red, B- hydrogen, C- acetic

A label on toothpaste box reads “Contains sodium bicarbonate (NaHCO₃)” What is the function of sodium bicarbonate in toothpaste?

1. Whitening only
2. Acts as a sweetener
3. Neutralises acid in mouth
4. Adds flavour

Answer: (c) Neutralises acid in mouth

When an acidic solution is diluted with water, what changes occur?

1. pH increases, conductivity decreases
2. pH decreases, conductivity increases
3. pH remains same, conductivity increases
4. Both pH and conductivity increase

Answer: (a) pH increases, conductivity decreases

A student mixes dilute hydrochloric acid with sodium hydroxide in a beaker. After the reaction, the temperature of the solution increases. Based on this observation, which of the following conclusions is most accurate?

1. The reaction is physical and reversible, as no new substance is formed.
2. The reaction is physical but irreversible, due to the temperature change.
3. The reaction is chemical and reversible, as the reactants can be regained by cooling.
4. The reaction is chemical and not reversible, as new substances are formed and energy is released.

Answer: (d) The reaction is chemical and not reversible, as new substances are formed and energy is released.