Question

If all the atoms touching one face plane are removed in solid $NaCl$ , then the formula of the compound left and the defect is given by :-

• A. $Na_{4}Cl_{3}$ , schottky defect
• B. $NaCl$ , schottky defect
• C. $Na_{2}Cl$ , frenkel defect
• D. $Na_{2}Cl$ , schottky defect

Answer 1

Answer: (B)

Rock salt structure
If all the atoms touching one face plane are removed then
No. of $Na^{+}$ left $=8\times \frac{1}{4}+1=3$
No. of $Cl$ left $=5\times \frac{1}{2}+4\times \frac{1}{8}=3$
Hence formula is $NaCl$
Also since equal number of cations and anions are missing defect is schottky defect.