Answer:
[tex]\large \boxed{40\, \%}[/tex]
Explanation:
1. Calculate the molar mass of NaCl
Na = 23 g
Cl = 35 g
Tot. = 58 g
2. Calculate the mass percent of Na
[tex]\text{\% of element} = \dfrac{\text{mass of element}}{\text{mass of compound}} \times 100 \, \% = \dfrac{\text{23 g}}{\text{58 g}} \times 100 \, \% =\mathbf{40\, \%}}[/tex]
[tex]\text{The percentage of Na in NaCl is $\large \boxed{\mathbf{40\, \% }}$}[/tex]
