Question

A. When an acidified solution of Mohr's salt is treated with potassium permanganate solution,
the ion which is oxidised is:
(A) NH4^+
(B) Fe2+
(C) SO4^2-
(D) MnO4^-
B. The relative size of isoelectronic species O^2-, F^-, Ne and Na^+ is determined by
(A) nuclear charge
(B) electron - electron repulsion in outer shell
(C) principal quantum number of valence shell
(D) nature of charge on the species​

Answer 1

Answer:

(B) Fe2+ is correct.

ferrous ion will get oxidized and become ferric ion.

Mohr’s salt has chemical formula that is [(NH4)2Fe (SO4)2] ⋅6H2O.

When it gets treated with potassium permanganate, the iron is oxidized by Mn.

As shown below  

MnO−4    +8H+     +5e       →     Mn2+   +    4H2O    

Fe2+→Fe3++e−  

(A) nuclear charge is correct.

The Isoelectronic Series is a group that contains atoms and ions which have the equal number of electrons in them.

For instance

(N3-, F-, Na+, Mg2+, Ne, Al3+, O2- ) these all atoms and ions have 10 electrons each.

Here raises the question of determining the size of these type of atoms and ions.

As their size are same so, their size is dependent on number of protons they have in them.  

In above mentioned atoms and ions N3- has 7 protons in it. Thus, its nuclear charge is lowest than all. Therefore, it has the lowest value of control on the electrons. So, it has greatest size.

Explanation: