Question

Assertion
$C{e^{4 + }}$ is a good analytical reagent.
Reason
$C{e^{4 + }}$ has a tendency to change to $C{e^{3 + }}$ .
A. Both assertion and reason are correct and Reason is the correct explanation of Assertion.
B. Both assertion and reason are correct but Reason is not the correct explanation for assertion.
C. Assertion is correct but the reason is incorrect.
D. Both assertion and reason are incorrect.

Answer 1

Reagents are the chemical substances that are used for the formation, measurement or detection of other substances during a chemical process. The reagent plays a vital role in the chemical reaction, it can act as a promoter or a poison to the reaction. The analytical reagent is the reagent that is used for analytical purposes so it should have a high standard of purity.

Complete step by step answer:
An analytical reagent is considered good if it has a high standard for purity. Cerium in the +4 state has an electronic configuration of xenon which is considered highly stable since xenon being an inert gas. Achieving inner gas configuration is the standard of achieving stability.
Cerium tends to change to a more stable +3 oxidation state by the loss or the gain of electrons, so the ions of cerium +4 in a solution can be considered as good oxidising agents.
The standard electrode potential of cerium +4 is found to be 1.74 V, which shows that it can oxidise water since the electrode potential of water -1.22 V. The cerium (IV) has sufficient kinetic stability due to the reaction rate being very slow and hence cerium (IV) is a good analytical reagent.

Therefore, the correct answer will be A.

Note: The potential of the individual half-cell cent is measured, we can only measure the difference between the two half cells which appears as the electromotive force (emf) and produces current.
For the measurement of the individual half-cell potential, we use the standard hydrogen electrode since we take the potential of hydrogen as zero.