Question

Chlorophyll extracted from the crushed green leaves was dissolved in water to make 2 L solution of Mg of concentration 48 ppm. The number of atoms of Mg in this solution is $x × 10^{20}$ atoms. The value of $x$ is ________. (Nearest integer)
(Given : Atomic mass of Mg is 24 g mol–1; NA = 6.02 × 1023 mol–1)

Answer 1

In 2L solution of Mg $→$ 96 mg of Mg
Number of atoms of Mg = $\frac {96×10^{−3}}{24}×N_A$
$=4×10^{−3}×6×10^{23}$
$=24×10^{20}$
$x=24$

So, the answer is $24$.