Acids, Bases and the pH Scale — O/L Science

What must I remember about Acids, Bases and the pH Scale?

• Acids: pH < 7; release H⁺ ions; sour taste; turn litmus red
• Alkalis: pH > 7; release OH⁻ ions; soapy feel; turn litmus blue
• Neutralisation: acid + base → salt + water
• pH scale: 0–14; 7 = neutral; lower = more acidic; higher = more alkaline

Test yourself (1 minute)

1. Indicators

   litmus (red=acid, blue=alkali), universal indicator, phenolphthalein

2. Stomach acid

   pH ~2 (HCl); baking soda: pH ~8–9

3. Strong acids

   HCl, H₂SO₄, HNO₃; weak acids: citric, acetic

Practise Acids, Bases and the pH Scale questions today

Must know

• HCl + NaOH → NaCl + H₂O (key equation)

Source: NIE O/L Science — Unit 5: Acids, Bases and Salts

What should I study first?

What comes next?

Next in the syllabus

Where does Acids, Bases and the pH Scale fit in the syllabus?

Grade 10 · Term 1 · Grade 11 · Term 1