Which Of The Following Is An Oxidation Reduction Reaction?
In chemistry, an oxidation-reduction reaction, also known as a redox reaction, is a chemical reaction that involves the transfer of electrons between two species. In an oxidation-reduction reaction, one species loses electrons and is said to be oxidized, while another species gains electrons and is said to be reduced.
The oxidation state of an atom or ion is a measure of its oxidation number. The oxidation state of an atom or ion can be determined by using the following rules:
- The oxidation state of an element in its elemental form is 0.
- The oxidation state of a monatomic ion is equal to its charge.
- The oxidation state of a polyatomic ion is the sum of the oxidation states of the atoms in the ion.
To determine whether a reaction is an oxidation-reduction reaction, we can look for a change in the oxidation state of the atoms or ions involved in the reaction. If the oxidation state of an atom or ion increases, then that atom or ion is oxidized. If the oxidation state of an atom or ion decreases, then that atom or ion is reduced.
Here are some examples of oxidation-reduction reactions:
- Combustion: The combustion of a hydrocarbon is an example of an oxidation-reduction reaction. In the combustion of methane, methane is oxidized to carbon dioxide and water, and oxygen is reduced to water.
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) In this reaction, the oxidation state of carbon in methane increases from -4 to +4, and the oxidation state of oxygen in oxygen decreases from 0 to -2.
- Electrolysis: Electrolysis is another example of an oxidation-reduction reaction. In electrolysis, an electric current is used to split a compound into its constituent elements. In the electrolysis of water, water is split into hydrogen and oxygen gas.
2 H2O(l) → 2 H2(g) + O2(g) In this reaction, the oxidation state of hydrogen in water decreases from +1 to 0, and the oxidation state of oxygen in water increases from -2 to 0.
Questions
1. Which of the following is an oxidation-reduction reaction?
Answer:
The answer is (A). In this reaction, copper is oxidized from 0 to +2, and silver is reduced from +1 to 0.
2. What is the oxidation state of copper in the following reaction?
Cu(s) + 2 AgNO3(aq) → 2 Ag(s) + Cu(NO3)2(aq) Answer:
The oxidation state of copper in copper metal is 0. In copper(II) nitrate, the oxidation state of copper is +2. Therefore, the oxidation state of copper in the reaction is 0 → +2.
3. What is the oxidation state of nitrogen in the following reaction?
2 NO(g) → N2(g) + O2(g) Answer:
In nitric oxide, the oxidation state of nitrogen is +2. In nitrogen gas, the oxidation state of nitrogen is 0. In oxygen gas, the oxidation state of oxygen is 0. Therefore, the oxidation state of nitrogen in the reaction is +2 → 0.
Additional Information
In addition to the change in oxidation state, there are other ways to identify oxidation-reduction reactions. One way is to look for the presence of a reducing agent and an oxidizing agent. A reducing agent is a substance that loses electrons and is oxidized. An oxidizing agent is a substance that gains electrons and is reduced.
Another way to identify oxidation-reduction reactions is to look for the presence of a spectator ion. A spectator ion is an ion that does not participate in the oxidation-reduction reaction.
Oxidation-reduction reactions are important in many chemical processes, including combustion, electrolysis, and respiration. They are also important in biology, where they are involved in many metabolic processes.
