Question

Which one of the following solutions of compounds show highest osmotic pressure? $(AB,A{B}_2$ and $A_2{B}_3$ are ionic compounds)

• A. $5.0M$ urea $i=1.0$ and temperature is $67^{\circ }C$
• B. $1.5M{A}_2{B}_3$ type $i=4.1$ and ternperature is $27^{\circ }C$
• C. $3.0MAB$ type $i=1.6$ and temperature is $27^{\circ }C$
• D. $2.5MA{B}_2$ type $i=2.5$ and temperature is $57^{\circ }C$

Answer 1

Answer: (D)

$\because \pi =$ ic $RT$, Thus

(a) $\pi$ for $5.0M$ urea is

$\pi =1\times 5\times R\times 340(T=67+273)$

$\pi =1700R$

(b) $\pi$ for $1.5M{A}_2{B}_3$ typè is $(i=4)$

$\pi =4.1\times 1.5\times R\times 300(T=27+273)$

$\pi =1800R.(\approx 1845)$

(c) $\pi$ for $3.0MAB$ type is $(i=1.6)$

$\pi =1.6\times 3\times R\times 300(T=27+273)$

$\pi =1440R$

(d) $\pi$ for $2.5MA{B}_2$ type is $(i=2.5)$

$\pi =2.5\times 2.5\times R\times 330(T=57+273)$

$\pi =2062.5R$