Question

The molanty of the solution obtained by mixing 200 ml of 2 M KOH with 800 ml of 4 M KOH
solution will be
A)2.6 M
B)4.2 M
C)1.8M
D)3.6M

Answer 1

Explanation:

Explanation:Given : Molarity of H

2

SO

4

= 18M

As, Molarity =

volume of solution

no. of moles of solute

i.e., 18moles of sulphuric acid is present per litre of solution.

Density=1.8g/mL {given}

Thus , mass of one litre of this solution ,

Density =

volume

mass

mass = density×volume

mass = 1.8×1000

mass = 1800g

Thus , mass of 1litre 18M H

2

SO

4

solution is 1800g or 1.8kg.

Now, mass of solution = mass of solute + mass of solvent

mass of solution = no. of moles of solute X molar mass of solute + mass of solvent

1800 = 18×98 + mass of solvent

mass of solvent = (1800−1764)g

mass of solvent = 36g

Now , molality of H

2

SO

4

solution is given by,

molality =

massofsolvent(inkg)

numberofmolesofsolute

molality =

36

18×100

molality = 500m

Hence, the molality of H

2

SO

4

solu

is 500m.

I hope it helps you ✌️