which best compares 1 mol of sodium chloride to 1 mol of aluminum chloride?\no both have the same molar…

Answer:

Both are made up of 6.02 x 10²³ formula units.

Explanation:

Step1: Recall mole - Avogadro's number concept

1 mole of any substance contains Avogadro's number ($6.02\times 10^{23}$) of formula units. Sodium chloride ($NaCl$) and aluminum chloride ($AlCl_{3}$) are ionic compounds and we use the term formula units for ionic compounds instead of molecules.

Step2: Analyze molar mass

The molar mass of $NaCl$ is $22.99 + 35.45=58.44\ g/mol$, and the molar mass of $AlCl_{3}$ is $26.98+3\times35.45 = 26.98 + 106.35=133.33\ g/mol$. So they do not have the same molar mass.

Step3: Analyze number of ions

1 mole of $NaCl$ dissociates into 1 mole of $Na^{+}$ and 1 mole of $Cl^{-}$ (2 moles of ions in total). 1 mole of $AlCl_{3}$ dissociates into 1 mole of $Al^{3 +}$ and 3 moles of $Cl^{-}$ (4 moles of ions in total). So they do not have the same number of ions.

Step4: Recall the term for ionic compounds

Since they are ionic compounds, we do not use the term'molecules' for them. But 1 mole of each contains $6.02\times 10^{23}$ formula units.