CBSE Class 12-science Answered

Dear Student,

To calculate moles of  NaOH:

Mass of  NaOH = 5 g

volume of solution = 450 mL = 450 × 10^-3 L

Molar mass of NaOH = 23 + 16 + 1 =  40 g mol^-1

Moles of NaOH = Mass of NaOH / Molar mass of NaOH

Moles of  NaOH = 5 g / 40 g mol^-1 = 0.125 mol

Molarity of solution = Moles of Solute / Volume of solution in L

Molarity = 0.125 mol / (450 × 10^-8 L) = 0.278 mol L^-1 = 0.278 M