a) With hydrogen
Hydrogen burns in oxygen to form water vapor.
A jet of hydrogen is burnt in oxygen, in an inverted funnel, as shown in figure (Fig.13.10). The product obtained, is sucked out through a test tube, kept immersed in cold water. The vapor condenses in the test tube to form water.
b) With carbon
When a red-hot piece of charcoal is taken in a deflagrating spoon and introduced into a jar containing oxygen gas, it bursts into flame producing carbon dioxide (Fig.13.11).
When some water is added into the gas jar and the solution tested with blue litmus, it turns red showing the formation of an acidic oxide.
c) With sulphur
Take some sulphur in a deflagrating spoon and heat it till it catches fire. Then introduce into a jar of oxygen. The sulphur will burn much more vigorously with a bluish flame, forming sulphur dioxide. Add some water into the jar and shake well. A test of this solution with blue litmus paper will turn it red showing the formation of an acidic oxide.
d) With phosphorus
Take a small piece of yellow phosphorus in a deflagrating spoon and introduce it into a jar of oxygen. It will start smouldering and give off white fumes of phosphorus (V) oxide. Take another yellow phosphorus piece and heat it gently till it catches fire; now introduce it into a jar of oxygen. It burns vigorously with a bright yellow color forming dense white fumes of phosphorus (V) oxide (Fig.13.13). Add water to both the jars and shake them. Test the solution with blue litmus. It turns red showing the formation of an acidic oxide.
