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MHT CET · Chemistry · Solid State

What is the percentage efficiency of packing in BCC structure?

  1. A \(32 \%\)
  2. B \(74 \%\)
  3. C \(26 \%\)
  4. D \(68 \%\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(68 \%\)

Step-by-step Solution

Detailed explanation

Packing efficiency:
\(\text {P.E. }=\frac{\mathrm{z} \times \frac{4}{3} \pi \mathrm{r}^3}{V}=\frac{2 \times \frac{4}{3} \times \pi\left(\frac{\sqrt{3} \mathrm{a}}{4}\right)^3}{\mathrm{a}^3}\) \(=\frac{\sqrt{3} \mathrm{a}}{8}=0.68\)
\({\left[\because \mathrm{z}=2, \mathrm{r}=\frac{\sqrt{3} \mathrm{a}}{4}, V=\mathrm{a}^3\right]}\)
In B.C.C., \(68 \%\) of total volume is occupied by atoms or ions.