Question

Fill the following observation table for given activity:
Activity: Iron nail dipped in copper sulphate solution for about half an hour
Observation Table :

Sr. No.	Experiment procedure	Observations
1.	Colour of \[CuS{O_4}\] soln. before the experiment.
2.	Colour of iron nail before the experiment.
3.	Colour of \[CuS{O_4}\] soln. after the experiment.
4.	Colour of iron nail after the experiment.

Answer 1

Hint: The above observations are of the experiment of when an iron nail dipped in copper sulphate solution for about half an hour then there are changes of colours in copper sulphate and iron nails. So here we have to write the observations in the given table.

Complete answer:
> We have studied about the reactivity series of metals where we have seen that iron is more reactive than copper hence it can displace copper from its salts. So displacement reaction occurs during the experiment, The displacement reaction taking place can be written as following;
             $Fe + CuS{O_4} \to FeS{O_4} + Cu$
Now observing the results of the experiments after half hours; The initial blue colour of \[CuS{O_4}\] is becomes to light green colour of iron sulphate and the initial colour of iron nails becomes reddish brown colour because of coating of copper metal on the nail. Now we can fill the given observation table:

Sr. No.	Experiment procedure	Observations
1.	Colour of \[CuS{O_4}\] soln. before the experiment.	Blue colour
2.	Colour of iron nail before the experiment.	Silver colour
3.	Colour of \[CuS{O_4}\] soln. after the experiment.	Light green colour of iron sulphate
4.	Colour of iron nail after the experiment.	Reddish brown colour

Note : We have observed that copper sulphate turns to pale green from bright blue colour and the iron nails acquire a reddish brown colour. This is because iron is more reactive than copper and its position is above in electrochemical series than copper hence iron is able to reduce copper from its salt solution to its element form.