Which of the following is NOT a redox reaction?

Question

Question

This question was previously asked in

AAI Junior Assistant (Fire Service) Official Paper (Held On: 15 Nov, 2022 Shift 2)

Answer 1

The correct answer is CaO(s) + H2O(l) → Ca(OH)2(aq).

Key Points

A redox reaction involves the transfer of electrons between two species.
In the reaction CaO(s) + H2O(l) → Ca(OH)2(aq), there is no change in the oxidation states of the elements involved.
Calcium oxide reacting with water to form calcium hydroxide is a simple combination reaction, not a redox reaction.
Redox reactions involve both oxidation and reduction processes, which are absent in the given reaction.
In the other options, either oxidation or reduction (or both) occurs, confirming them as redox reactions.

Additional Information

Redox Reaction:
- Redox is short for reduction-oxidation, a type of chemical reaction that involves a transfer of electrons between two species.
- It includes two processes: oxidation (loss of electrons) and reduction (gain of electrons).
Oxidation State:
- The oxidation state is a number assigned to an element in a compound that represents the number of electrons lost or gained by an atom of that element in the compound.
- It is used to determine whether a redox reaction has occurred.
Combination Reaction:
- A combination reaction is a type of chemical reaction where two or more substances combine to form a single product.
- In the reaction CaO + H2O → Ca(OH)2, calcium oxide and water combine to form calcium hydroxide.
Electron Transfer:
- Electron transfer is a fundamental concept in redox reactions where electrons move from one chemical species to another.
- The substance that loses electrons is oxidized, and the one that gains electrons is reduced.