‘Both combination reaction and displacement reaction fall in the category of redox reactions’. Do you agree? If so discuss this aspect with suitable examples
Answers
Answer:
Explanation:
Types of Redox Reactions (Oxidation and Reduction)
Redox reactions can be primarily classified into five different types:
Combination Reactions
Decomposition Reactions
Displacement Reactions
Disproportionate Reactions
Let us go through each type of redox reaction one-by-one.
1) Combination Reactions
In this type of oxidation and reduction reactions, that is, redox reactions, two species of any atoms or molecules combine to form a single species of the compound. The schematic representation of the reaction is
Type of Oxidation and Reduction reaction
This type of reaction refers to redox reactions only when both the species (A & B) or either of the species are present in their elemental form. This type of redox reaction (oxidation and reduction) reaction is just the opposite of the decomposition reaction.Type of oxidation and reduction reactions
Combustion Reactions
It is a subtype of combination reaction in which one of the species will always be elemental dioxygen. Refer to the examples below.
types of oxidation and reduction reactions
2) Decomposition Reactions
It is just the opposite of combination reactions. This type of reactions involves breaking down of a single compound into two or more different compounds. However, at least one product out of the two or more components must be in its elemental form. Examples of this category of oxidation and reduction reactions are
redox (oxidation and reduction) reaction
redox (oxidation and reduction) reaction
All the above reactions take place under heat as a necessary condition.
Exception
However, not all the decomposition reactions are redox process/reactions. For instance:
3) Displacement Reactions
In this type of reactions, an atom or an ion in a compound is substituted by another element. The schematic representation of the equation is
redox-oxidation and reduction-reaction
In the above reaction, the X atom replaces atom Y from the compound YZ. There are mainly two types of displacement reactions:
Metal-displacement reactions
Non-metal displacement reactions
i) Metal-Displacement Reactions
In this type of displacement reaction, an elemental metal displaces a metallic compound present in the reaction. The metal which is a better reducing agent displaces the other metal. Refer to the examples below
redox reactions
ii) Non-Metal Displacement Reactions
In this type of reactions, either a metal or a non-metal will displace another non-metal of a compound present in the reaction. Usually, the non-metal undergoing displacement is hydrogen. However, in certain cases, halogens or oxygen undergoing displacement can occur.
First, we will discuss the reactions involving hydrogen displacement. According to the capability of reducing metal or non-metal, following non-metal displacement reaction cases occur:
Good reducing agents displace hydrogen in cold water. All alkali metals and few alkaline earth metals such as Calcium, Strontium, and Barium are very good reducing agents.oxidation and reduction (redox) reactionstype of redox reactions
In another case, less active metals can react with steam to form hydrogen gas. Examples of less active metals are magnesium and iron.
There are metals that cannot displace hydrogen when reacting in cold water. However, these metals can displace hydrogen from acids. Refer to the examples below
Metals such as cadmium and tin do not react with steam. However, it reacts with acids and forms dihydrogen gas.
There are metals such as silver and gold that are very less reactive. They generally occur in the native form and are not reactive even with dilute HCl.
Reactivity of Metals and Non-Metals
Reactivity of Metals
The determination of the order of the reactivity of metals is possible by observing the rate of evolution or rate of displacement of hydrogen from dilute/aqueous acids and water. The order of reactivity can also be determined by the tendency of metals to lose electrons which in turn signifies the metals reducing capacity.
For instance, the rate of reactivity of Na than Mg. The rate of reactivity of Mg is faster than Fe. Therefore, Fe reacts at the slowest rate. Additionally, metals like silver and gold do not react altogether. The order of reactivity of metal can be seen in metal activity series.
Reactivity of Non-Metals
Non-metals also have activity series similar to metals. As we know, non-metals have the electron accepting tendency whereas metals have the electron losing tendency. Thus, the reactivity of non-metals depends on the oxidizing power of a non-metal. If we consider the halogen group, the oxidizing power of group number 17 decreases from fluorine to iodine