Acids and Bases

Question 1

What is the pH of a neutral substance?

Answer 1

7

Question 2

Recall the range of pH values for acidic solutions.

Answer 2

1-6

Question 3

Recall the range of pH values for alkaline solutions.

Answer 3

8-14

Question 4

What ions do acids form in water?

Answer 4

H⁺

Question 5

What ions do alkalis form in water?

Answer 5

OH⁻

Question 6

What colours does a litmus indicator turn in acidic, neutral and alkaline solutions?

Answer 6

• Acidic: Red
• Neutral: Purple
• Alkaline: Blue

Question 7

What colours does a methyl orange indicator turn in acidic, neutral and alkaline solutions?

Answer 7

• Acidic: Red
• Neutral: Yellow
• Alkaline: Yellow

Question 8

What colours does a phenolphthalein indicator turn in acidic, neutral and alkaline solutions?

Answer 8

• Acidic: Colourless
• Neutral: Colourless
• Alkaline: Pink

Question 9

How does the concentration of H⁺ ions affect the pH of an acidic solution?

Answer 9

The greater the concentration of H⁺ ions, the lower the pH

Question 10

How does the concentration of OH⁻ ions affect the pH of an alkaline solution?

Answer 10

The greater the concentration of OH⁻ ions, the higher the pH

Question 11

What is a ‘base’?

Answer 11

Any substance that reacts with an acid to form a salt and water only

Question 12

What is an alkali?

Answer 12

A base that is soluble in water

Question 13

Describe what a neutralisation reaction is.

Answer 13

A reaction between an acid and a base, in which H⁺ ions from the acid react with OH⁻ ions from the alkali to form water