Gr 9 NATURAL SCIENCES: HFST 2.5 What is the pH value?

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What is the pH value of a neutral substance?

Zero

Equal to 7 (correct)

Above 7

Below 7

What is the characteristic of acids that can be used to distinguish them from bases?

Taste sour and feel rough (correct)

Can be corrosive

Taste bitter and feel slippery

Turn blue litmus red

What is the function of an indicator in a solution?

To neutralize the solution

To change the pH of the solution

To show whether the solution is acidic or basic (correct)

To make the solution corrosive

What is the pH range of the pH scale?

1 to 14 Signup and view all the answers

Who first described the term 'pH' in 1909?

Søren Peter Lauritz Sørensen Signup and view all the answers

Which of the following is an example of a base?

Bicarbonate of soda Signup and view all the answers

What does 'pH' stand for?

Power of Hydrogen Signup and view all the answers

What is the pH of a neutral substance?

pH 7 Signup and view all the answers

Which of the following is an example of a strong acid?

Lemon juice Signup and view all the answers

What is used to measure the pH of a solution?

Indicators Signup and view all the answers

Which of the following is a characteristic of both acids and bases?

Corrosiveness Signup and view all the answers

What does a pH value of 7 indicate?

A neutral substance Signup and view all the answers

What is the purpose of an indicator in a solution?

To show whether the solution is acidic or basic Signup and view all the answers

What is the pH range of acidic substances?

Below 7 Signup and view all the answers

Which of the following substances is an example of an acid?

Vinegar Signup and view all the answers

What is the main difference between lemon juice and orange juice in terms of pH?

Lemon juice has a lower pH than orange juice. Signup and view all the answers

Why is it important to maintain the right pH in swimming pool water?

To ensure the water is neutral. Signup and view all the answers

What is the characteristic of a strong acid?

It has a pH close to 1. Signup and view all the answers

What is the purpose of 'pH balanced' shampoo?

To make the shampoo neutral, matching the pH of the hair. Signup and view all the answers

What is the relationship between the pH of a substance and its acidity?

As the pH increases, the substance becomes more basic. Signup and view all the answers

What is the primary reason why lemon juice has a lower pH than orange juice?

Lemon juice has a higher concentration of hydrogen ions Signup and view all the answers

What is the purpose of maintaining a neutral pH in skin soap?

To balance the pH of the skin Signup and view all the answers

What happens to the pH of a substance as it becomes more basic?

The pH increases towards 14 Signup and view all the answers

Why is it important to monitor the pH of swimming pool water?

To ensure the water is within a safe range for swimmers Signup and view all the answers

What is the relationship between the pH of a substance and its strength as an acid or base?

A stronger acid has a lower pH, and a stronger base has a higher pH Signup and view all the answers

What is the primary purpose of using an indicator in a solution?

To identify whether the solution is acidic or basic Signup and view all the answers

What is the characteristic that distinguishes acidic taste from basic taste?

Sour taste indicates an acid, while bitter taste indicates a base Signup and view all the answers

What happens to the pH value of a solution when an acid is added to it?

The pH value decreases Signup and view all the answers

What is the relationship between the feel of a substance and its classification as an acid or base?

Acids feel rough, while bases feel slippery Signup and view all the answers

What is the range of pH values for neutral substances?

pH 7 only Signup and view all the answers