A set of solutions is prepared using 180 g of
water as a solvent and 10 g of different nonvolatile solutes A, B and C. The relative
lowering of vapour pressure in the presence of
these solutes are in the order :
[Given, molar
mass of A = 100 g mol–1; B = 200 g mol–1;
C = 10,000 g mol–1]
Solution
Relative lowering in vapour pressure (RLVP)
<br><br>= ${{P - {P_s}} \over P} = {n \over {n + N}}$
<br><br>n $\to$ moles of solute
<br>N $\to$ moles of solvent
<br><br>$\therefore$ (RLVP)<sub>A</sub> = ${{{{10} \over {100}}} \over {{{10} \over {100}} + {{180} \over {18}}}}$
<br><br>(RLVP)<sub>B</sub> = ${{{{10} \over {200}}} \over {{{10} \over {200}} + {{180} \over {18}}}}$
<br><br>and (RLVP)<sub>C</sub> = ${{{{10} \over {10000}}} \over {{{10} \over {10000}} + {{180} \over {18}}}}$
<br><br>$\therefore$ (RLVP)<sub>A</sub> > (RLVP)<sub>B</sub> > (RLVP)<sub>C</sub>
<br><br>So, A > B > C
About this question
Subject: Chemistry · Chapter: States of Matter · Topic: Gas Laws
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