Question

Calculate the value of Avogadro's number from the following data.

[Z=4, density is 2.16 g/ml^2 radius of anion and cation is 281 pm]

Answer 1

Solution:-

As we know that,

$a=2(r^{+}+r^{-})=2\times 281=562pm$

$d=\frac{ZM}{N_{A}V}$

$\because 4NaCl$ are present in unit cell.

$\therefore Z=4$

$d=2.165g/{cm}^{-3}\left(\text{Given}\right)$

Molecular mass $\left(M\right)=58.5g$

$\therefore 2.165=\frac{4\times 58.5}{{(562\times {10}^{-10})}^3\times N_A}$

$\Rightarrow N_A=\frac{4\times 58.5}{{(562\times {10}^{-10})}^3\times 2.165}=6.01\times {10}^{23}$