What amounts do you compare when measuring concentration

Explanation:

The concentration is a measure of how much solute is present in certain amount of solvent or solution. There are many quantitative expressions for the concentration. Some of those expressions are: percentage, molarity, molality, molar fraction, among others.

This table shows the expressions for some concentration measures, showing the amounts compared.

Concentration                         amounts compared in form of ratio

Percentage, mass/mass         (mass of solute / mass of solution) × 100  

Percentage, vol./vol.                (vol. of solue / vol. of solution) × 100

Molarity                                     (moles of solute / liters of solution)

Molality                                      (moles of solute / Kg of solvent)

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.

the answer is 0.42 is that is an option. this question provides no info