The acids prepared from the minerals of the earth are called mineral acids. Mineral acids are man made acids.
Hydrochloric acid, Sulphuric acid and Nitric acid. Concentrated mineral acids are very dangerous.
Question :Why the dilution of a concentrated acid should always be done by adding concentrated acid to water gradually with stirring and not by adding water to concentrated acid.
Answer When a concentrated acid is added to water for preparing a dilute acid, then the heat is evolved gradually, and easily absorbed by the large amount of water (to which acid is being added).
If, however, water is added to concentrated acid to dilute it, then a large amount of heat is evolved at once.
This heat changes some of the water to steam explosively which can splash the acid on our face or clothes and cause acid burns and can even break the glass.
Chemical Properties of Acid and Base
Acid + Metal → Salt + Hydrogen gas
Zn (s) + H2SO4 (aq) – ZnSO4 (aq) + H2 (g
experiment between sulphuric acid and zinc results in evolution of hydrogen gas by bubble test
Only hydrogen gas burns making a ‘pop’ sound.
This shows that hydrogen gas is evolved in the reaction of dilute sulphuric acid with zinc metal (taken in the form of zinc granules).
Acids react with metal carbonates (and metal hydrogencarbonates) to form carbon dioxide gas
Metal carbonate + Acid — Salt + Carbon dioxide + Water
Metal hydrogen carbonate + Acid — Salt + Carbon dioxide + Water
When dilute hydrochloric acid reacts with sodium carbonate, then sodium chloride, carbon dioxide and water are formed
chemical reaction between sodium carbonate with hydrochloride acid to form sodium chloride and carbon dioxide and water.
The carbon dioxide gas is formed in the form of brisk effervescence (the rapid escape of small bubbles of gas from the liquid).
When dilute hydrochloric acid reacts with sodium hydrogen carbonate, then sodium chloride, carbon dioxide and water are formed
On passing the carbon dioxide gas evolved through lime water
conversion of lime water into white precipitate of calcium carbonate by passes of carbon dioxide gas
Calcium carbonate (White ppt.) Makes Lime Water Milky
On passing excess Carbon Dioxide white precipitate formed first dissolves due to the formation of a soluble salt calcium hydrogencarbonate, and the solution becomes clear again
conversion of white precipitate of calcium carbonate into clear solution of calcium hydrogen carbonate
limestone, marbleand chalk are the different forms of the same chemical compound ‘calcium carbonate’. Even the egg-shells are made of calcium carbonate.
some compound made up of calcium carbonate
Acids react with bases (or alkalis) to form salt and water
the reaction between an acid and a base to form salt and water is called a neutralisation reaction
Base + Acid → Salt + Water
neutralization reaction between base sodium hydroxide and acid hydrochloride acid to form salt sodium chloride and water.
Reaction of Metallic Oxides with Acids
Metal oxide + Acid → Salt + Water
chemical reaction between copper oxide and hydrochloride acid to form copper chloride and water
metallic oxides are said to be basic oxides and are basic in nature