Explanation of Science class 8 ncert ch 4 activity 4.4
Answers
Answer:
Take a small amount of powdered sulphur in a deflagrating spoon and heat it. If deflagrating spoon is not available, you may take a metallic cap of any bottle and wrap a metallic wire around it and give it the shape shown in Fig. 4.4 (a).
As soon as sulphur starts burning, introduce the spoon into a gas jar/ glass tumbler [Fig. 4.4 (a)]. Cover the tumbler with a lid to ensure that the gas produced does not escape. Remove the spoon after some time. Add a small quantity of water into the tumbler and quickly replace the lid. Shake the tumbler well. Check the solution with red and blue litmus papers [Fig. 4.4 (b)].
The name of the product formed in the reaction of sulphur and oxygen is sulphur dioxide gas. When sulphur dioxide is dissolved in water sulphurous acid is formed. The reaction can be given as follows:
Sulphur dioxide (SO2) + Water (H2O) → Sulphurous acid (H2SO3)
The sulphurous acid turns blue litmus paper red. Generally, oxides of non-metals are acidic in nature.
Recall the name of some of the laboratory acids and bases you have read in Class VII. Note down their names in Table 4.4. Identify the metal or nonmetal present in them which forms oxides with oxygen.