Question

When an electric current is passed through \(\mathrm{H}_{2} \mathrm{O},\) the \(\mathrm{H}_{2} \mathrm{O}\) decomposes to form \(\mathrm{H}_{2}\) and \(\mathrm{O}_{2} .\) Which of the following correctly represents this reaction? F. \(2 \mathrm{H}_{2}+\mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}\) G. \(\mathrm{H}_{2}+2 \mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}\) H. \(2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{H}_{2}+\mathrm{O}_{2}\) J. \(2 \mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{H}_{2}+2 \mathrm{O}_{2}\)

Short answer

Answer: \(2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{H}_{2}+\mathrm{O}_{2}\) (Option H)

Step-by-step solution

Check option F

The given equation in option F is: \(2 \mathrm{H}_{2}+\mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}\) Setting up a list of elements and compare their numbers on the left side and right side: Element | Left side | Right side --------|-----------|----------- H | 4 | 4 O | 2 | 2 The numbers of elements are equal on both sides. However, option F represents the combination of hydrogen and oxygen to form water, not the decomposition of water. Therefore, option F is not correct.

Check option G

The given equation in option G is: \(\mathrm{H}_{2}+2 \mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}\) Setting up a list of elements and compare their numbers on the left side and right side: Element | Left side | Right side --------|-----------|----------- H | 2 | 4 O | 4 | 2 The numbers of elements are not equal on both sides. Option G is incorrect.

Check option H

The given equation in option H is: \(2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{H}_{2}+\mathrm{O}_{2}\) Setting up a list of elements and compare their numbers on the left side and right side: Element | Left side | Right side --------|-----------|----------- H | 4 | 4 O | 2 | 2 The numbers of elements are equal on both sides. Option H represents the decomposition of water into hydrogen and oxygen, which is the correct process. Therefore, option H appears to be correct.

Check option J

The given equation in option J is: \(2 \mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{H}_{2}+2 \mathrm{O}_{2}\) Setting up a list of elements and compare their numbers on the left side and right side: Element | Left side | Right side --------|-----------|----------- H | 4 | 2 O | 2 | 4 The numbers of elements are not equal on both sides. Option J is incorrect.

Conclusion:

Based on the above steps, the correct representation of the decomposition of water (\(\mathrm{H}_{2}\mathrm{O}\)) into hydrogen gas (\(\mathrm{H}_{2}\)) and oxygen gas (\(\mathrm{O}_{2}\)) when an electric current is passed through it is: Option H: \(2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{H}_{2}+\mathrm{O}_{2}\)

Key concepts

Electrolysis of Water

Electrolysis of water is a fascinating process where electrical energy is converted into chemical energy, specifically to decompose water (H₂O) into hydrogen gas (H₂) and oxygen gas (O₂). This procedure involves passing an electric current through water which has some electrolyte, like salt, to enhance its conductivity.
In this process, water acts as an electrolyte where the water molecules lose electrons (oxidation) at the anode to form oxygen and gain electrons (reduction) at the cathode to form hydrogen. It's important to ensure safety during this experiment since the gases produced are combustible and need to be collected carefully.
Electrolysis is not only critical in teaching about chemical reactions but is also practical; for example, in producing hydrogen for fuel cells. Understanding the fundamentals of this procedure is vital for students who may apply these principles in future scientific or industrial applications.

Chemical Equation Balancing

One of the fundamental skills in chemistry is the ability to balance chemical equations. Balancing chemical equations is like a puzzle where you need to make sure that the number of atoms of each element is the same on both sides of the reaction. It's based on the law of conservation of mass which states that matter cannot be created or destroyed in a chemical reaction.
To balance an equation, you may need to place coefficients in front of the chemical formulas to ensure the number of atoms of each element are equal on both sides. The reaction between hydrogen and oxygen to form water, as explained in the solution, requires careful balancing to reflect the correct stoichiometry. Students often find this skill challenging at first, but practice improves proficiency. It's essential to present clear and stepwise approaches to support their understanding.

Chemical Decomposition

Chemical decomposition, also known as analysis or breakdown, is a type of chemical reaction where a compound is broken down into simpler substances. This can occur through various means such as heating, the introduction of electricity, or with the help of a catalyst.
In the context of the exercise, electrolysis is the method used to decompose water into hydrogen and oxygen gases. Decomposition reactions are opposite to synthesis reactions, like how water is formed when hydrogen combusts with oxygen. Learning about decomposition reactions equips students with a deeper comprehension of chemical reactivity and the types of changes compounds can undergo under different conditions.
This concept is crucial since it can be applied broadly, from understanding how batteries work to analyzing metabolic reactions in the body. Effective teaching about decomposition should not only involve the conceptual knowledge but also the application in real-life contexts.