Question

Which half-reaction correctly describes an oxidation?

Answer 1

Answer:

The last choice is oxidation.

Explanation:

The this is a reaction in which the oxidation number of chromium metal

( 0 ) goes the an oxidation number of 3 in Cr3+.

Answer 2

Answer : The correct option is, $Cr(s)\rightarrow Cr^{3+}(aq)+3e^-$

Explanation :

Redox reaction : It is a reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is a 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 a 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.

The correct oxidation-half reaction will be :

$Cr(s)\rightarrow Cr^{3+}(aq)+3e^-$

In this half oxidation reaction, the oxidation state of 'Cr' changes from (0) to (+3) that means the oxidation state increases that means it shows oxidation.