2e (Acids, alkalis and titrations)

Question 1

Litmus (colour in acid, alkali)

Answer 1

Red, blue

Question 2

Methyl orange(colour in acid, alkali)

Answer 2

red, yellow

Question 3

Phenolphthalein (colour in acid, alkali)

Answer 3

Colourless, pink

Question 4

pH scale ranges

Answer 4

• Strongly acidic –> 0-3 (red - orange)
• Weakly acidic –> 4-6 (orange-yellow)
• Neutral –> 7 (green)
• Weakly alkaline –> 8-10 (green-blue)
• Strongly alkaline –> 11-14 (blue-purple)

Question 5

An acid is source of…

Answer 5

Hydrogen ions (H+)

Question 6

An alkali is source of…

Answer 6

hydroxide ions (OH-)

Question 7

Bases

Answer 7

• Metal oxides, metal hydroxides and ammonia are bases
• Bases neutralise acids by combining with the hydrogen ions in them