The big picture
Every idea here is one rule and one bench.
| Idea | Remember | Example |
|---|---|---|
| The shelf again | Blue to red is an acid, red to blue a base. | a blue strip that stays blue cannot tell base from neutral |
| What acids share | Every acid frees H⁺; a dissolved base frees OH⁻. | glucose has hydrogen but frees no H⁺ |
| Metals and carbonates | A reactive metal gives salt and H₂; a carbonate gives salt, water and CO₂. | Zn + H₂SO₄ → ZnSO₄ + H₂; copper gives no hydrogen |
| The pH scale | Usually 0 to 14; a lower pH means more H⁺. | universal indicator, red to violet |
| Living windows | Each place has its own pH range. | enamel wears below pH 5.5 |
| Neutralisation | Acid and base give salt and water. | NaOH + HCl → NaCl + H₂O |
| Crystals with water | Heat drives out held water; water brings it back. | CuSO₄·5H₂O → CuSO₄ + water |
Open Chapter 2 of your NCERT book. It is called Acids, Bases and Salts. It goes further into each test.