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:
The solution's new volume is 1.68 L
Explanation:
Dilution is the procedure to prepare a less concentrated solution from a more concentrated one, and simply consists of adding more solvent. So, in a dilution the amount of solute does not vary, but the volume of the solvent varies.
In summary, a dilution is a lower concentration solution than the original.
The way to do the calculations in a dilution is through the expression:
Ci*Vi=Cf*Vf
where C and V are concentration and volume, respectively; and the i and f subscripts indicate initial and final respectively.
In this case, being:
- Ci= 7 M
- Vi= 0.60 L
- Cf= 2.5 M
- Vf=?
Replacing:
7 M*0.60 L= 2.5 M* Vf
Solving:
Vf= 1.68 L
<u><em>The solution's new volume is 1.68 L</em></u>