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

Explanation:

Step1: Recall mole concept

One 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 are represented by formula - units, not molecules.

Step2: Analyze molar mass

The molar mass of $NaCl$ is $M_{NaCl}=22.99 + 35.45=58.44\ g/mol$, and the molar mass of $AlCl_3$ is $M_{AlCl_3}=26.98+3\times35.45 = 26.98 + 106.35=133.33\ g/mol$. So they don't have the same molar mass.

Step3: Analyze number of ions

One formula - unit of $NaCl$ dissociates into 2 ions ($Na^+$ and $Cl^-$), and one formula - unit of $AlCl_3$ dissociates into 4 ions ($Al^{3 +}$ and 3 $Cl^-$). So 1 mole of each does not have the same number of ions.

Step4: Recall nature of ionic compounds

Ionic compounds like $NaCl$ and $AlCl_3$ are not composed of molecules in the traditional sense. They are composed of formula - units. One mole of any substance contains $6.02\times 10^{23}$ formula - units.

Answer:

Both are made up of $6.02\times 10^{23}$ formula units.