A redox reaction has occurred ________.
1 answer:
Answer : The correct option is, (a) when a substance reacts with elemental oxygen.
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
From the given options we conclude that a redox reaction has occurred when a substance reacts with elemental oxygen. Because elemental oxygen will oxidize the metal and itself get reduced. Thus, it is a redox reaction.
For example :
This reaction is a redox reaction in which magnesium shows oxidation due to change in oxidation state from (0) to (+2) and oxygen shows reduction due to change in oxidation state from (0) to (-2).
Hence, the correct option is, (a) when a substance reacts with elemental oxygen.
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Answer: 2. Decomposition
Explanation:
Synthesis reaction is a type of chemical reaction in which two reactants combine to give a single product.
Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.
lithium carbonate → lithium oxide + carbon dioxide
Single replacement reaction is a type of chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
A double replacement reaction is one in which exchange of ions take place.