Question

explain why Ce+4 is good oxidizing agent while Eu2+ IS GOOD REDUCING AGENT IN AQUESOUS SOLUTION

Answer 1

In aqueous solution, Ce4+ converts to Ce3+ by gaining an electron so it acts as a good oxidising agent while Eu2+ in aqueous solution chenges to Eu3+ suggesting that it is agood reducing agent by donating electron.

Answer 2

Answer: Because cerium does not have any electrons to be lost but Europium has.

Explanation:

Oxidizing agent is defined as the specie which oxidizes the other substance and itself gets reduced. This specie gains electrons.

Reducing agent is defined as the specie which reduces the other substance and itself gets oxidized. This specie looses electrons.

Cerium and Europium are f-block element or lanthanoids. Atomic number of cerium is 58 and atomic number of europium is 63.

Electronic configuration of both the elements is:

$Ce(Z=58):[Xe]4f^15d^16s^2\\Eu(Z=63):[Xe]4f^75d^06s^2$

Cerium has only 4 electrons and $Ce^{4+}$ has no valence electrons are left. Hence, it can only gain electrons and not loose extra electrons and act as oxidizing agent.

Europium has 9 valence electrons and $Eu^{2+}$ has 7 electrons left. Hence, it can easily loose more electrons and can act as reducing agent.