Question

JEE mains 20 July ,chemistry.
4.5 grams of a substance [molar mass=90g/mol] is dissolved in 250ml solution,then molarity of solution is

Answer 1

Answer:

Ans. 0.2 M

Sol. Given -

WT of solute = 4.5g

molecular mass of solute = 90g

WT of solution = 250ml = 250 x 10-3 L

Molarity = M = no of moles of solute ÷ Volume of solution(L)

no of moles of solute = given wt / Molecular mass

n = 4.5/90 = 0.05 moles

M = n / volume

M = 0.05 / 250 x 10-3

M = 0.05 x 1000 / 250

M = 0.05 x 4 = 0.2M