The solution containing 3 ~g urea (molar mass 60 ) per dm ^3 of water and another solution containing 4.5 ~g of solute A per dm ^3 boils at same temperature, then what is molar mass of A?

Step-by-step solution

T _ b = K _ b m molality ( m )= moles of solute mass of water ( kg ) 1L H ₂ O =1 dm ^3 H ₂ O =1 ~kg H ₂ O Density of water =1 ~kg / L Boiling points are same for two solutions, aligned & T _ b ₁ = T _ b ₂ & ~m ₁= m ₂ aligned aligned & 3 / 60 1 = 4.5 / M 1 & M = 60 4.5 3 & =90 ~g / mol aligned