Question

What is the molarity of the solution formed by mixing 0.20mol of sodium hydroxide with enough water to make 150 ml of solution?

Answer 1

Molarity is defined as the number of moles of solute in 1 L of solution 
number of NaOH moles present - 0.20 mol 
volume of solution - 150 mL 
since molarity is taken as number moles of solute in 1000 mL
if 150 mL contains - 0.20 mol 
then 1000 mL should contain - 0.20 / 150 x 1000 = 1.33 mol 
therefore molarity is 1.33 M