Robert bought a bottle of cleaning agent to clean his kitchen sink. He noticed a warning label on the bottle — "Use with Caution". Curious about its nature, he tested the solution using litmus. The red litmus turned blue, while the blue one remained unchanged. Later he learned that bases like sodium hydroxide, ammonium hydroxide are commonly used for cleaning as they can dissolve grease and organic waste. Such substances can be hamful to the skin and eyes if not handled properly.

(a) Why is a basic solution used in drain cleaners ?

(b) What does a change in the colour of litmus indicate ?

(c) Why was the warning label given on the cleaning agent ?

(d) How does this example show the practical application of bases in everyday life ?

(a) A basic solution is used in drain cleaners because bases can dissolve grease, oils, fats and organic waste that often block kitchen sinks and drains. Strong bases like sodium hydroxide break down these substances and help clear the blockage.

(b) A change in the colour of litmus indicates the acidic or basic nature of a substance. In this case, red litmus turned blue, which shows that the cleaning agent is basic/alkaline in nature. Blue litmus remaining unchanged also supports that it is not acidic.

(c) The warning label was given because many cleaning agents contain strong bases, which can be corrosive or irritating. They may harm the skin, eyes or respiratory tract if touched, splashed or inhaled. Therefore, they should be handled carefully.

(d) This example shows that bases have practical uses in everyday life. In homes, basic substances are used in drain cleaners and cleaning agents because they help remove grease and organic dirt. However, it also shows that such useful chemicals must be used safely and carefully.