Reactions of acids
Acids, bases and alkalis
produce when dissolved in water. Common acids are hydrochloric acid (HCl), sulfuric acid (H₂SO₄) and nitric acid (HNO₃).
A is a substance that an acid to form a salt and water. Metal oxides and metal hydroxides are bases.
An is a base that dissolves in water, producing hydroxide ions (OH⁻). Sodium hydroxide (NaOH) is an alkali.
Key terms
Four reactions of acids
| Acid reacts with | Products | Example |
|---|---|---|
| A | salt + hydrogen | Mg + 2HCl → MgCl₂ + H₂ |
| A metal oxide | salt + water | CuO + H₂SO₄ → CuSO₄ + H₂O |
| A metal hydroxide | salt + water | NaOH + HCl → NaCl + H₂O |
| A metal carbonate | salt + water + | CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂ |
Only metals above hydrogen in the reactivity series react with dilute acids.
The reactions with metals and carbonates fizz, because a gas is given off. Hydrogen burns with a ; carbon dioxide turns .
Key terms
Naming salts
A is made when the hydrogen in an acid is replaced by a metal. Its name has two parts:
- The first part comes from the (or the metal in the base or carbonate).
- The second part comes from the .
| Acid | Salt ending | Ion |
|---|---|---|
| Hydrochloric acid | chloride | Cl⁻ |
| Sulfuric acid | sulfate | SO₄²⁻ |
| Nitric acid | nitrate | NO₃⁻ |
Zinc + sulfuric acid → zinc sulfate. Magnesium oxide + nitric acid → magnesium nitrate.
To write the formula, balance the charges: Mg²⁺ and NO₃⁻ give Mg(NO₃)₂; Na⁺ and SO₄²⁻ give Na₂SO₄.