Question

The radius of divalent cation ${M^{2 + }}$ is 94ppm and that of divalent anion ${X^{2 - }}$ is 146ppm. Thus ${M^{2 + }} + {X^{2 - }}$ has.
A.NaCl structure
B.Linear structure
C.CsCl structure
D.ZnS structure

Answer 1

The classification of various structures can be done by finding the radius ratio of the cation and anion. Depending upon the range of the radius ratio, we can classify the structures.
Formula used:
The radius ratio of cation and anion is given by:
$\dfrac{{{r_{cation}}}}{{{r_{anion}}}}$

Complete step by step answer:
The radius ratio (also known as radius ratio rule), is the ratio of the ionic radius of the cation to the ionic radius of the anion in a cation-anion compound.
It is given that the radius of cation is 94 ppm
And radius of anion is 146 ppm
Therefore, according to the given formula we will find the radius ratio
$\dfrac{{{r_{cation}}}}{{{r_{anion}}}} = \dfrac{{94}}{{146}}$
Therefore, the ratio is $0.6438$
Since, for NaCl structure, the radius ratio lies between 0.410-0.732
Thus, we have NaCl structure.
Basically, NaCl has a cubic unit cell. It is also known as salt and it is an essential compound our body uses to absorb and transport nutrients, to maintain blood pressure and to maintain the right balance of fluid. It is a crystal structure with a face centered cubic bravais lattice and two atoms in the basis.

Hence, option A is correct.

Note:
The ions in a compound such as sodium chloride are arranged in a lattice structure. The ions cannot move to conduct the electric current. But when an ionic compound melts, the charged ions are free to move. Therefore, molten ion compounds conduct electricity.