molarity is defined as the number of moles of solute in 1 L of solution.
the number of moles of NaOH = mass present / molar mass of NaOH
molar mass of NaOH = 22.99 + 16.00 + 1.008 = 40.00 g/mol
therefore NaOH moles = 29.5 g / 40.00 g/mol = 0.738 mol
the number of NaOH moles in 2.45 L solution - 0.738 mol
therefore number of NaOH moles in 1 L = 0.738 mol / 2.45 L = 0.301 mol/L molarity of NaOH = 0.301 M
