Question

Statement 1 : If the length of the unit cell of $LiCl$ having $NaCl$ structure is $5.14\mathring{A}$, the ionic radius of $C{l}^{-}$ ion is $1.82\mathring{A}$.
Statement 2 : Anion-anion contact is retained in $LiCl$ structure because anions constitute the lattice.

• A. If both Statement $1$ and Statement $2$ are true and the statement $2$ is the correct explanation of the statement $1$
• B. If both Statement $1$ and Statement $2$ are true but statement $2$ is not the correct explanation of the statement $1$
• C. If Statement $1$ is true but Statement $2$ is false
• D. If Statement $1$ is false but Statement $2$ is true

Answer 1

Answer: (A)

If anion-anion contact is retained, then as shown in the adjoining figure.

Interionic distance of $LiCl=a/2$
$=5.14\mathring{A}/2=2.57\mathring{A}$
$BC=\sqrt{A{B}^2+A{C}^2}$
$=\sqrt{(2.57{)}^2+(2.57{)}^2}$
$=3.63\mathring{A}$
Radius of $C{l}^{-}$ ion $=\frac{1}{2}BC$
$=\frac{1}{2}\times 3.63=1.81\mathring{A}$
Hence, statement $2$ is the correct explanation of statement $1$.