Question

A unit cell of sodium chloride has four formula units. The edge of length of the unit cell is $0.564$ nm. What is the density (in g/cc) of sodium chloride?

• A. $1$
• B. $2.16$
• C. $4.32$
• D. None of the above

Answer 1

The correct option is B $2.16$

$d=\frac{zM}{N_A\times V}$
For NaCl, $z=4$
$d=\frac{4\times 58.5}{6.023\times {10}^{23}\times (0.564\times {10}^{-7}{)}^3}$
$d=\frac{234}{6.023\times 0.179\times {10}^2}$
$d=2.16$ $gc{m}^{-3}$