Question

for teteanedsal woids
[
begin{array}{l}
a=sqrt{2} R
& R=frac{sqrt{2} a}{2}-0
end{array}
]
Here, ( R=250 ) pm Now if ( r^{prime} ) be the radins of word to a diagonal of cube
[
begin{array}{l}
2(R+r)=sqrt{3} a
text { Muiding } 25 mathrm{m}
frac{2(R+2)}{R}=frac{sqrt{3} alpha times 2}{sqrt{29}}
1+frac{2}{R}=frac{sqrt{3}}{12}
frac{C}{R}=0.225
end{array}
]
for feraneacal woid, ( frac{x^{+}}{c^{-}}=0.225 )
( begin{aligned} text { or we can say } R &=0.225 times 250 &=56.25 mathrm{mm} end{aligned} )
Ans ( =(2) Q^{+}(text {radin }=56 mathrm{m}) )

# he following 34. A crystalline solid AB has NaCl type struct radius of B-ion is 250 pm. Which of the follo cation can be made to slip into tetrahedral sit crystals of A+B-? (1) P+ (radius = 180 pm) (2) Q+ = (radius = 56 pm) (3) R+ = (radius = 200 pm) (4) S+ = (radius = 150 pm)

Solution