Show wet blue and red litmus papers over the watch glass containing soap solution one by one. Which litmus paper shows a colour change ?

Show a wet red litmus paper on the mouth of the boiling tube. What change can you observe?

If we show a red litmus paper over ammonia gas, what change can be observed?

If we show a red litmus paper over ammonia gas. What change can be observed?

A blue litmus paper is dipped into an aqueous solution of NH_4NO_3 . Is there any colour change? Substantiate your answer.

Keep the litmus paper for some more time at the mouth of the boil-ing tube and then observe its colour change. What is the change occurred?

In order to wash clothes with water containing dissolved calcium hydrogen carbonates, which cleaning agent will you prefer and why? Soaps or synthetic detergents give one advantage of soaps over synthetic detergents?

The solutions of ZnSO4 , FeSO4, CuSO4 and AgNO3 are taken in four different test tubes. Suppose, an iron nail is kept immersed in each one: In which test tube the iron nail under goes a colour change?, What is the reaction taking place here?