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?

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

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

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?

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?

Keep two carbon rods immersed in copper sulphate solution. Then pass electricity through the solution. i) At which electrode does colour change occur-anode or cathode? ii) Is there any change in the blue colour of the copper sulphate solution? iii) Write down the chemical equations for the changes occurring here?