Grade 7 : Science (Curiosity) - 2. Acids, Bases, Neutral (Set 2)

Question 1

Sarah squeezed a lemon into a glass of water to make lemonade.

Based on its characteristic taste, what kind of substance is lemon juice?

Accepted Answer

A) Acid

Answer

B) Base

Answer

C) Neutral

Answer

D) Indicator

Question 2

David is washing his hands with a bar of soap, and he notices it feels slippery to the touch.

What kind of substance typically feels slippery to the touch?

Accepted Answer

B) Base

Answer

A) Acid

Answer

C) Neutral

Answer

D) Solvent

Question 3

A science experiment requires a neutral liquid to rinse equipment and ensure no contamination from acidic or basic residues.

Which common substance is considered neutral?

Accepted Answer

C) Distilled water

Answer

A) Vinegar

Answer

B) Baking soda solution

Answer

D) Orange juice

Question 4

Emily dips a piece of blue litmus paper into an unknown solution. The paper immediately turns red.

What does this color change indicate about the solution?

Accepted Answer

B) It is an acid

Answer

A) It is a base

Answer

C) It is neutral

Answer

D) It is an indicator

Question 5

Mark tests a liquid in his laboratory using red litmus paper. He observes that the red litmus paper changes to a blue color.

What type of substance is Mark testing?

Accepted Answer

B) Base

Answer

A) Acid

Answer

C) Neutral

Answer

D) Salt

Question 6

A scientist carefully mixes an acidic solution with a basic solution in precise proportions until the resulting solution shows no reaction to either red or blue litmus paper.

What is the primary outcome of this chemical reaction?

Accepted Answer

C) Neutralization

Answer

A) Formation of a new acid

Answer

B) Formation of a new base

Answer

D) Increased acidity

Question 7

Lily is exploring natural ways to test for acids and bases using common household items in her kitchen.

Which of the following is a common natural indicator that can be used for this purpose?

Accepted Answer

C) Turmeric

Answer

A) Litmus paper

Answer

B) Phenolphthalein

Answer

D) Methyl orange

Question 8

Grandpa Jim often experiences a burning sensation in his stomach due to excess acid. He takes an antacid tablet to relieve this discomfort.

What type of substance are antacids, and how do they help in this situation?

Accepted Answer

B) Base, to neutralize the stomach acid

Answer

A) Acid, to dilute the stomach acid

Answer

C) Neutral, to coat the stomach lining

Answer

D) Indicator, to change the color of stomach acid

Question 9

A farmer's soil is too acidic for his crops to grow well, leading to poor yields. He decides to add lime (calcium oxide), a basic substance, to the soil to improve its condition.

Why would adding lime help the acidic soil?

Accepted Answer

B) Lime neutralizes the soil acidity

Answer

A) Lime makes the soil more acidic

Answer

C) Lime adds nutrients to the soil directly

Answer

D) Lime acts as a fertilizer

Question 10

During a chemistry class, students measure the pH of an unknown solution and find its pH value to be 11.

Based on the pH scale, what can be concluded about this solution?

Accepted Answer

D) It is strongly basic

Answer

A) It is strongly acidic

Answer

B) It is weakly acidic

Answer

C) It is neutral