Question

Assertion If edge length of unit cell of $LiCl$, having $NaCl$ type structure, is $5.14\,\mathring{A}$, the ionic radius of $Cl ^{-}$ion is $1.82\, \mathring{A}$.
Reason Anion-anion contact is retained in $LiCl$ structure because anions constitute the lattice.

• A. If both Assertion: and Reason: are true and the Reason: is the correct explanation of the Assertion:
• B. If both Assertion: and Reason: are true but the Reason: is not the correct explanation of the Assertion:
• C. If Assertion: is true but Reason: is false
• D. If both Assertion: and Reason: are false

Answer 1

Answer: (A)

If anion-anion contact is retained,
$4 r^{-} =\sqrt{2} a$
$r^{-} =\frac{\sqrt{2} \times 5.14}{4}$
$=1.82\, \mathring{A}$
Thus, Reason is the correct explanation of Assertion.