Which of the following is displaced by 'Cu'? 1.Fe2+ 2.Ag+ 3.Zn2+ 4.Al3+

Explanation:

This problem tests our knowledge/understanding of the electro-chemical series.

Electrochemical series or activity series is a list that describes the arrangement of elements in order of their increasing electrode potential values.

In the electro-chemical series metals placed above can displace metals below from their salt solutions.

In this question given the series as  stated

1. Fe2+

2.Ag+

3.Zn2+

4.Al3+  

In the series we have metals stated as Zn>Fe>Cu>Ag.

Cu will displace silver Ag+  because it is below it in the series

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.