Answer :
is the oxidizing agent and Fe is the reducing agent.
Explanation :
Reducing agent : It is defined as the agent which helps the other substance to reduce and itself gets oxidized. Thus, it will undergo oxidation reaction.
Oxidizing agent : It is defined as the agent which helps the other substance to oxidize and itself gets reduced. Thus, it will undergo reduction reaction.
The balanced redox reaction is :

The half oxidation-reduction reactions are:
Oxidation reaction : 
Reduction reaction : 
In order to balance the electrons, we multiply the oxidation reaction by 4 and reduction reaction by 3 then added both equation, we get the balanced redox reaction.
Oxidation reaction : 
Reduction reaction : 

In this reaction,
is the reducing agent that loses an electron to another chemical species in a redox chemical reaction and itself gets oxidized and
is the oxidizing agent that gain an electron to another chemical species in a redox chemical reaction and itself gets reduced.
Thus,
is the oxidizing agent and Fe is the reducing agent.
Hey there!
Solid Sodium and water will react spontaneously and release energy. This is based on the reactivity series. Sodium is a highly reactive metal and hence, it is placed at the top of the reactivity series. This is because it loses its outermost electron very readily. When it comes in contact with water, it reacts with it violently to form sodium hydroxide and hydrogen gas. This reaction is exothermic and hence, accompanied with a release of energy. Gold lies at the bottom of the reactivity series as it is very stable and does not give away its outermost electrons easily. Therefore, when it comes in contact with water, there is no reaction and no release of energy.
The Triassic period is one of the geological periods and is the shortest of the Mesozoic era. Cambrian is the older era than the Triassic period.
<h3>What is Cambrian and triassic period?</h3>
The Triassic period existed 250 -200 million years ago and started after the vastest and most extreme devastation ever. It is the 1st period of the Mesozoic and is known for the movement of the Dinosaurs on the land, flying pterosaurs and swimming plesiosaurs and ichthyosaurs.
The Cambrian is the period of the Paleozoic era and is the most important period because of the appearance of many animals. In this period, the temperature raised on the planet and the ice sheets melted at a very dangerous rate leading to mass devastation.
Therefore, option A. <u>Cambrian</u> is older than the Triassic period.
Learn more about Cambrian and Triassic periods here:
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