Question

 

Using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. Use 3 – 4 sentences in your explanation.

Answer 1

Addition of sodium chloride or calcium chloride would decreases the freezing point. since the freezing point of water is 0 deg.

we know delta Tf= i. Kf . m where m molality; i vandewal coefficient.

if i value is more dippression in freezing point will be more

for NaCl i=2 (na+ and cl-); for CaCl2 i=3 (Ca+2 and 2Cl-).

Cacl2 addition will lower the freezing point to more extent than NaCl.

But Calcium chloride produces an exothermic reaction when mixed with ice, which means that it literally heats up when it comes in contact with ice and heats up ice. so Calcium chloride is used in the melt the ice on a slick sidewalk.

Answer : Calcium Chloride

Sodium chloride does not produce any exothermic reaction.