Q.
If 15 g of a solute in 100 g of water makes the solution freeze at −1∘C , then 30 g. of the same solute in 100 g of water will make the solution freeze at:
We know that, m=ΔT⋅W1000Kf.w (As the solute and solvent are same in both cases), hence: W1W1=ΔT1 and W2W2=ΔT2 or W1⋅W2W1⋅W2=ΔT2ΔT1100×3015×100=ΔT2[(0)−(−1)]ΔT2=2×1=2∘ Hence, now water will freeze at (0−2)=−2∘C