Grade 7 : Science (Curiosity) - 2. Acids, Bases, Neutral (Set 6)

Question 1

Which of the following common household substances is generally considered a neutral substance?

Accepted Answer

C) Distilled water

Answer

A) Lemon juice

Answer

B) Baking soda solution

Answer

D) Vinegar

Answer

E) Soap solution

Question 2

A student drops a piece of blue litmus paper into an unknown liquid. The litmus paper immediately turns red.

Based on this observation, what can be concluded about the unknown liquid?

Accepted Answer

A) It is acidic.

Answer

B) It is basic.

Answer

C) It is neutral.

Answer

D) It is a salt solution.

Answer

E) It is an alkali.

Question 3

Turmeric solution is used as a natural indicator. What color change would you observe if you add a basic solution to a turmeric indicator?

Accepted Answer

B) Turns red

Answer

A) Stays yellow

Answer

C) Turns green

Answer

D) Turns blue

Answer

E) Turns purple

Question 4

The process in which an acid and a base react to form a salt and water is known as:

Accepted Answer

D) Neutralization

Answer

A) Oxidation

Answer

B) Reduction

Answer

C) Precipitation

Answer

E) Decomposition

Question 5

A person is experiencing indigestion due to excess acid in their stomach.

Which type of substance would be most effective as an antacid to relieve this condition?

Accepted Answer

B) A basic substance

Answer

A) An acidic substance

Answer

C) A neutral substance

Answer

D) A salty substance

Answer

E) A strong acid

Question 6

Which of the following properties is characteristic of a base?

Accepted Answer

A) Soapy to touch

Answer

B) Sour taste

Answer

C) Turns blue litmus red

Answer

D) Reacts with metals to produce hydrogen gas

Answer

E) Turns phenolphthalein colorless

Question 7

While conducting an experiment, a student accidentally spills a highly concentrated acidic solution on their skin.

What immediate first aid action should be taken?

Accepted Answer

D) Rinse the affected area immediately with plenty of water.

Answer

A) Apply a strong base to neutralize it.

Answer

B) Cover it with a bandage.

Answer

C) Rub the affected area vigorously.

Answer

E) Apply oil to dilute the acid.

Question 8

A student tested four different solutions (P, Q, R, S) with universal indicator paper and recorded the following colors:

Solution	Color with Universal Indicator
P	Red
Q	Blue
R	Green
S	Yellow

Which solution is most likely basic?

Accepted Answer

B) Solution Q

Answer

A) Solution P

Answer

C) Solution R

Answer

D) Solution S

Answer

E) Solutions P and S

Question 9

Which statement accurately describes the pH scale?

Accepted Answer

A) A pH of 7 indicates a neutral solution.

Answer

B) A pH value less than 7 indicates a basic solution.

Answer

C) A pH value greater than 7 indicates an acidic solution.

Answer

D) The pH scale ranges from 1 to 10.

Answer

E) Only acids have a pH value.

Question 10

A farmer observes that their soil is too acidic, causing poor crop growth.

What common substance could the farmer add to the soil to reduce its acidity?

Accepted Answer

C) Slaked lime (calcium hydroxide)

Answer

A) Vinegar

Answer

B) Ammonium sulfate (acidic fertilizer)

Answer

D) Lemon juice

Answer

E) Nitric acid