Q32Short answer
The density of 3 molal solution of NaOH is 1.110 g mL . Calculate the molarity of the solution.
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65 g of zinc will liberate 22.7 L H2 22.7 32.65 g Zn × = L = 11.35 L 65.3 g Zn 2 32. 3 molal solution of NaOH means that 3 mols of NaOH are dissolved in 1000 g of solvent. ∴ Mass of Solution = Mass of Solvent + Mass of Solute = 1000 g + (3 × 40 g) = 1120 g 1120 Volume of Solution = mL = 1009.00 mL 1.110 –1 (Since density of solution = 1.110g mL ) Since 1009 mL solution contains 3 mols of NaOH Number of moles of solute ∴ Molarity = Volume of solution in litre 3 mol = × 1000 = 2.97 M 1009.00