| What ions do acids form when dissolved in water? | Acids form H+ ions when dissolved in water |
| What ions do alkalis form when dissolved in water? | Alkalis form OH- ions when dissolved in water |
| What's the difference between strong and weak acids in terms of ionisation? | Strong acids - fully ionise in aqueous solutions (hydrochloric, sulfuric and nitric acid)
Weak acids - partly ionise in aqueous solutions (carbonic, ethanoic and citric acid), the reversible arrow (shown below) indicates a reversible reaction meaning only a fraction of the acid ionises |
| What happens when acids ionise? | They split, releasing H+
EG, HCl -> H^(+) + Cl^(-) |
| What is the difference between an alkali and a base? | Base - any substance that reacts with an acid forming a salt
Alkali - any SOLUBLE substance that reacts with an acid forming a salt |
| Describe the relationship between the PH value of an acid and the concentration of hydrogen ions. | As the PH scale decreases by 1 unit, the concentration of hydrogen ions increases ×10 |
| Why is it better to use a PH probe rather than universal indicator when measuring PH? | PH probes are more accurate as they don't require human judgement (guessing the colour shade) |
| What are acids and bases? | Acids - substances that forms aqueous solutions with a PH less than 7 (this is because they release H+ ions in water)
Bases - substances with PH greater than 7 (if a base dissolves in water, it is an alkali) |
