Verified Solution • 2025–26 Session moderate

QJEEM23Chd711: JEE Main 2023 Chemistry - Class 12 JEEM23Chd711 Solution: Sea water contains 29.25 %   NaCl and 19 %   MgCl 2…

Sea water contains 29.25% NaCl and 19% MgCl2 by weight of solution. The normal boiling point of the sea water is _____________ ∘C (Nearest integer)

Assume 100% ionization for both NaCl and MgCl2

Given : Kb(H2O)=0.52 K kg mol−1

Molar mass of NaCl and MgCl2 is 58.5 and 95 g mol−1 respectively.

Step-by-Step Verified Solution

Amount of solvent = 100 - (29.25 + 19) = 51.75 g

Now, we can calculate the boiling point elevation using the given formula:

ΔTb = [(2 × 29.25 × 1000) / (58.5 × 51.75) + (3 × 19 × 1000) / (95 × 51.75)] × 0.52

ΔTb = 16.075

The boiling point of the sea water is the normal boiling point of water plus the change in boiling point:

Boiling point of sea water = 100 °C + 16.075 °C = 116.075 °C

Rounding to the nearest integer, the normal boiling point of the sea water is approximately 116 °C.

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