Question

The number of $Na$ atom in $46\, g \,Na$ (atomic weight of $Na= 23$) is

• A. $6.023\times 10^{23}$
• B. $2$
• C. $1$
• D. $12.046\times 10^{23}$

Answer 1

Answer: (D)

$12.046\times 10^{23}$

Answer 2

$\because 23\, g$ of $Na$ contains
$=6.023 \times 10^{23}$ atoms $\therefore 1\, g$ of Na contains
$=\frac{6.023 \times 10^{23}}{23}$ atoms
$\therefore 46\, g$ of Na contains
$=\frac{6.023 \times 10^{23}}{23} \times 46$ atoms
$=12.046 \times 10^{23}$ atoms