A sample of KCl is placed in 50 ml of solvent. What should be the mass of the sample for the molarity to be 2M ?
7.45 g
7.81 g
6.81 g
7.0 g
As we learnt,
Molarity -
Molarity (M) = (Number of moles of solute)/(volume of solution in litres)
- wherein
It is defined as the number of moles of the solute in 1 litre of the solution.
Number of Moles = molarity x volume
= 2 x 0.05 = 0.1
So, mass = (39 + 35.5) x 0.01g = 7.45 g
Option 1)
7.45 g
Option 2)
7.81 g
Option 3)
6.81 g
Option 4)
7.0 g
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