Some properties of dilute acid with their proof through experiments are discussed as follows:
All dilute acids are sour in taste. We have already seen that the acidic foods are sour in taste. However, one should remain careful not to taste any acid in the laboratory. If your tongue comes in contact with any of these acids, they will instantly corrode your tongue. You may try the taste of tamarind/ lemon instead which will tell you tartaric/ citric acid taste sour.
Acids are corrosive in nature. If you put a piece of metal in acid, the outer edge of the metal will be corroded.
3. Litmus Test:
Acid turns blue litmus into the red. For example: simply take 2-3 mL hydrochloric acid in a test tube and add a blue litmus to it. You will see the blue colour will turn into red. You may try the same test with H2SO4, HNO3 or any other acids. Even tamarind or pickles will show you the same result.
4. Reaction with Reactive Metals:
Acid undergoes reaction with reactive metals (K, Na, Mg etc.) and produces the salt of that metal and hydrogen as well. As for example, Mg undergoes reaction with sulfuric acid and produces MgSO4 and H2 gas.
5. The reaction between Dilute Acid and Metallic Carbonate:
Dilute acids undergo reactions with metallic carbonate to produce salt, water and carbon dioxide. For instance, calcium carbonate and dilute HCl undergo reaction to produce calcium chloride salt, water and carbon dioxide gas. The gas comes out in bubbles.
If we channel this produced carbon dioxide in lime water, the lime water will turn turbid. The reaction will be:
Hence, the lime water looks turbid (muddy) as insoluble CaCO3 is produced. This turbid lime water again turns opaque when extra CO2 is channelled in it.
At his stage, CO2 and H2O undergo reaction with CaCO3 to produce soluble calcium bicarbonate [Ca(HCO3)2] which makes the water look opaque.
Similarly, the metallic carbonates undergo such kind of reactions with dilute sulfuric acid or dilute nitric acid and produce sulfate or nitrate salts.
6. The reaction between Dilute Acids and Metallic Bicarbonates:
Metallic bicarbonates or metallic hydrogen carbonates also undergo reactions with dilute acids and produce salts, water and carbon dioxide. For Example:
7. Reaction between Dilute Acids and Metal’s Hydroxides (Alkali):
Dilute acids undergo reactions with metal’s hydroxides to produce salt and water. It is a neutralizing reaction. For example, if dilute HCl acid solution is slowly added to dilute NaOH solution, it will produce NaCl (salt) and H2O (water).
8. The reaction between Dilute Acids and Metal’s Oxides:
Acids undergo reaction with metal’s oxides and produce salt and water. The oxides are usually of alkaline nature. That is why the reactions here are also neutralizing reactions.
In the same way, copper oxide undergoes reaction with dilute sulfuric acid and forms copper sulfate (CuSO4) and water.
Or, calcium oxide and nitric acid undergo reaction to produce Ca(NO3)2 (calcium nitrate) and water.