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| Properties of Acids |
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| Taste |
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| Acids are generally sour in taste. |
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| Change of colours with indicators |
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| Indicators are substances that undergo a change of colour with a change of acidic, neutral or basic medium. Acids change the colour of indicators as given in the table. |
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| Action on Metals |
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| a) Metals above hydrogen in the metal activity series generally react with dilute acids to form their respective salt and hydrogen. |
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Metal + Acid  Salt + Hydrogen |
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| b) Very active metals like potassium, sodium and calcium also react similarly, but tend to explode when combining with acids. |
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| c) Nitric acid (of variousconcentrations) usually exhibits oxidizing property, rather than acidic properties. Metals such as magnesium combine with extremely dilute (1%) nitric acid to liberate hydrogen. |
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| Action with Basic Oxides |
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| Oxides that can add on hydroxyl ions to their molecules are called basic oxides. These oxides get neutralized when they react with acids. |
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| Basic oxide + Acid Salt + Water |
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| Action with Basic Hydroxides |
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| Acids undergo neutralization reaction with basic hydroxides to form salt and water. |
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| Basic hydroxide + Acid Salt + Water |
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| Action with Carbonates and Hydrogen carbonates |
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| Acids react with carbonates and hydrogen carbonates to form their respective salt, water and carbon dioxide. |
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| Carbonate/Bicarbonate + Acid Salt + Water + Carbon dioxide |
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| Action with Sulphites and Bisulphites |
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| Acids react with sulphites and bisulphites to form their respective salt, water and sulphur dioxide. |
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| Sulphite/Bisulphites + Acid Salt + Water + Sulphur dioxide |
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| With Metal Sulphides |
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| Acids react with metal sulphides to form their respective salt and hydrogen sulphide. |
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| Metals sulphide + Acid Salt + Hydrogen sulphide |
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