Question

Calculate molality of the mixture of solution produced by mixing 25 % W/W of NaOH solution with
15 %W/W
solution ? (Molecular mass of NaOH = 40 gm/mole)
(A) 12.74 m
(B) 5.5 m
(C) 9.0 m
(D) 4.0 m​

Answer 1

Answer:

Calculate molality of mixture of solution produced by mixing 25% W/W of NaOH solution with 15% W/W solution.

❥Let x be the mass of solution. Mass of NaOH= 100. x×20.

❥Molar mass of NaOH=40g. ∴ Number of moles= ( 100. 20x. )/40= ...

❥Now mass of solvent in the solution= x− 100. 20x. = 100. ...

❥∴ Molality= (80x/100) x/200. ×1000=6.25M.

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