The Solid State Ques 25
25. The edge length of a face centred unit cubic cell is $508 pm$. If the radius of the cation is $100 pm$, the radius of the anion is
[1996]
(a) $288 pm$
(b) $398 pm$
(c) $154 pm$
(d) $618 pm$
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Answer:
Correct Answer: 25.(c)
Solution:
(c) For $f c c$, the edge length of the unit cell, $a=r+2 R+r$
where, $R=$ Radius of anion $& r=$ radius of cation
$\therefore \quad 508=2 \times 100+2 R \Rightarrow R=154 pm$
BETA
