Question

Which of the following 0.10 m aqueous solution will have the lowest freezing point ?

• A. $Al_2(SO_4)_3$
• B. $C_6H_{12}O_6$
• C. $C_{12}H_{12}O_{11}$
• D. $KI$

Answer 1

Answer: (A)

$Al_2(SO_4)_3$

Answer 2

Depression in freezing point is a colligative property which depends upon the amount of the solute. $\Delta T _{ f }= i \times K _{ f } \times m$ $i _{\left( C _{12} H _{22} O _{11}\right)}=1, i _{( KI )}=2, i _{\left( Al _{2}\left( SO _{4}\right)_{3}\right)}=5, i _{\left( C _{5} H _{10} O _{5}\right)}=1$ as, $\Delta T _{ f } \alpha i$ thus, $\Delta T _{ f }(\max )$ is for $0.10 m$ alluminium sulphate and Hence, has lowest Freezing point.