Question

A compound $CuCl$ has face-centred cubic structure. Its density is $3.4gc{m}^{-3}$ . The length of unit cell is

• A. $8.734\stackrel{o}{A}$
• B. $5.834\stackrel{o}{A}$
• C. $5.783\stackrel{o}{A}$
• D. $8.153\stackrel{o}{A}$

Answer 1

Answer: (C)

Molecular mass of $CuCl=99$ $Z=4$ for face-centred cubic cell from the formula Density $=\frac{Z\times M}{V\times N_A}=\frac{4\times 99}{a^3\times 6.023\times {10}^{23}}$ Or $3.4=\frac{4\times 9}{a^3\times 6.023\times {10}^{23}}$ Or $a=5.783\times {10}^{-8}cm=5.783\stackrel{o}{A}$