Question

Calculate the boiling point elevation for a solution prepared by adding 10 g of MgCl₂ to 200 g of water, assuming MgCl₂ is completely dissociated.

(K_b for Water = 0.512 K kg mol⁻¹, Molar mass MgCl₂ = 95 g mol⁻¹)

Answer 1

We know that

ΔT_b = iK_bm

\[\ce{MgCl2 -> \underset{1 + 2}{Mg^{2+} + 2Cl^-}}\]

i = 3

Here, m = `("W"_"B" xx 1000)/("M"_"B" xx "W"_"A")` = 0.526

ΔT_b = iK_bm

= 3 × 0.512 × 0.526

= 0.808 K