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Water Electrolysis Experiment - Quiz

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What does the water electrolysis experiment most directly prove?

Water Electrolysis Experiment - Quiz - Quiz Questions

Test your understanding of water molecule composition, electrolysis principles, and experimental phenomena through the following exercises.

1. What does the water electrolysis experiment most directly prove?

A. Water is a mixture of hydrogen and oxygen gases
B. Water is composed of hydrogen and oxygen elements
C. Water is an indivisible atom
D. Molecules can be further divided in chemical reactions

2. In the water electrolysis experiment, what gas is collected in the test tube connected to the negative electrode?

A. Oxygen
B. Hydrogen
C. Air
D. Carbon dioxide

3. Theoretically, the volume ratio of hydrogen to oxygen produced is approximately:

A. 1 : 2
B. 2 : 1
C. 8 : 1
D. 1 : 8

4. To enhance the conductivity of water, a small amount of which substance can be added to the water?

A. Sugar
B. Table salt (NaCl)
C. Sodium hydroxide (NaOH) or dilute sulfuric acid
D. Petroleum

5. What is the most appropriate phenomenon for testing the gas produced at the anode (positive electrode)?

A. The gas ignites with a pale blue flame
B. A glowing splint relights
C. A popping sound is produced
D. Limewater turns cloudy

6. [Calculation] If $20\text{ml}$ of hydrogen is collected at the cathode in the experiment, how many milliliters of oxygen should theoretically be collected at the anode?

A. $40\text{ml}$
B. $20\text{ml}$
C. $10\text{ml}$
D. $5\text{ml}$

7. In an experiment investigating 'the effect of voltage on water electrolysis rate', which of the following is the independent variable?

A. The rate of bubble production
B. The voltage setting of the DC power supply
C. The mass of sodium hydroxide added to the water
D. The distance between the electrodes

8. Which description correctly describes the energy conversion in water electrolysis?

A. Chemical energy is converted to electrical energy
B. Electrical energy is converted to chemical energy
C. Thermal energy is converted to chemical energy
D. Light energy is converted to electrical energy

9. In actual experiments, the observed volume ratio of hydrogen to oxygen is often slightly greater than $2:1$. The main reason is:

A. The produced hydrogen is mixed with air
B. Oxygen is more soluble in water than hydrogen
C. One of the test tubes leaked
D. Hydrogen molecules are larger than oxygen molecules

10. If a regular dry cell battery is used instead of the DC power supply, no obvious bubbles are observed. The most likely reason is:

A. The dry cell voltage ($1.5\text{V}$) is too low to overcome the decomposition potential and internal resistance
B. Dry cells are not alternating current
C. There is no electrolyte inside the dry cell
D. Water doesn't like dry cells