Study the given diagram representing the electrolysis of water carefully and select the correct observations.

I) Water levels in both test tubes A and B fall gradually.

II) The volume of gas collected at the positive electrode is double the

the volume of the gas collected at the negative electrode.

III) Gas collected in test tube B makes the things burn brightly while the

gas collected in test tube A burns with a pop sound.

IV) This reaction is an example of an endothermic reaction.

In this detailed analysis of the electrolysis of water diagram, we will go over the important observations and their scientific explanations based on the principles of electrolysis.

Observations

1. Water levels in both test tubes A and B fall gradually:

   In the electrolysis of water diagram, as the water undergoes dissociation into hydrogen and oxygen gases, the levels of water in both test tubes (A and B) gradually decrease. This is because the electrolysis process splits water into its constituent gases, causing a reduction in water volume.

2. The volume of gas collected at the positive electrode is double the volume of gas collected at the negative electrode:

   In the electrolysis of water diagram, hydrogen gas is collected at the negative electrode (cathode) and oxygen gas at the positive electrode (anode). According to the balanced chemical equation for the electrolysis of water (2H₂O → 2H₂ + O₂), the volume of hydrogen gas produced is double that of the oxygen gas. Therefore, the volume of gas collected at the negative electrode is twice that at the positive electrode.

3. Gas collected in test tube B makes the things burn brightly while the gas collected in test tube A burns with a pop sound:

   In the electrolysis of water diagram, oxygen gas is collected in test tube B and hydrogen gas in test tube A. Oxygen, being a strong oxidizing agent, supports combustion and helps objects burn brightly. On the other hand, hydrogen gas, collected in test tube A, burns with a characteristic "pop" sound due to its flammability.

4. This reaction is an example of an endothermic reaction:

   The electrolysis of water is an endothermic reaction, meaning it requires energy to break the bonds of water molecules. In the electrolysis of water diagram, electrical energy is supplied to the water, breaking it down into hydrogen and oxygen gases. This process absorbs energy, which is characteristic of endothermic reactions.

Conclusion

By studying the electrolysis of water diagram, we can observe the fundamental principles of electrolysis in action. These observations confirm that the process is not only an interesting chemical reaction but also a demonstration of the conversion of electrical energy into chemical energy, with specific characteristics for each of the products formed.