Considering acetic acid dissociates in water, its dissociation constant is . If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at , provided pure water freezes at 0°C. .

Question

Considering acetic acid dissociates in water, its dissociation constant is . If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at , provided pure water freezes at 0°C.  . (Nearest integer)

Given: , density of acetic acid is , molar mass of water = 18 g mol⁻¹, molar mass of acetic acid = 60 g mol⁻¹, density of water = 1 g cm⁻³

Acetic acid dissociates as

Canvas Classes · Accepted Answer

Strategy:
 First, find the molality of the acetic acid in water. Then, calculate the degree of dissociation () using the given . Use  to find the van't Hoff factor (), and finally calculate the freezing point depression.

Step 1: Calculate the molality ()
- Mass of Acetic acid = 
- Moles = 
-

Step 2: Find degree of dissociation ()
.

Step 3: Calculate van't Hoff factor ()
For , .

Step 4: Calculate

Step 5: Express as 
.
Rounding to the nearest integer: 19.

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