Match the boiling point with `K_(b)` for x,y and z, if molecular weight of x,y and z are same.
`{:(,b.pt.,"K"_("b")),(x,100,0.68),(y,27,0.53),(z,253,0.98):}`

Explanation

Molal elevation constant may be calculated as,
`K_(b_(1000))=(RT_0^(2))/(1000L_v)" "("where, "T_0="boiling point of pure solvent "L_v="latent heat of vaporization.")`
`=(RT_0^(2))/(1000(DeltaH_v)/m_B)" "L_v=(DeltaH_v)/m_b`
(here, `DeltaH_v` = molar latent heat of vaporization).
`(RT_0^(2)m_B)/(1000DeltaH_v)" "m_B="molar mass of solute."`
`K_(b_(1000))=(RT_0^(2)m_B)/(1000DeltaS_v)" here,"DeltaS_v="entropy of vaprization"`
By considering `Delta `as almost constant, `K_vpropT_v`.
`:.K_b(x)=0.68,K_b(y)=0.53" and "K_b=0.98`