Question

What is the molarity for a solution that is composed of 80.00 grams of sodium hydroxide dissolved in 2.0 L of water?

1.0 M
2.0 M
4.O M
40.0 M
Which of the following must be measured in the lab in order to calculate the molarity of a solution?

The mass of the solute
The mass of the solvent
The volume of the solution
The mass of the solute and the volume of the solution

Answer 1

Molar mass of sodium hydroxide is 40 gms. So 80 gms. is 2 mol.

2 mol in 2L water. Thus, molarity is $2/2=1 M$ (Answer)

Molarity is mass of solute per unit volume of solution. Thus, to calculate molarity mass of the solute and the volume of the solution must be found