Question

In countries nearer to polar region, the roads are sprinkled with \(\text{CaCl}_2\). This is:

• A. to minimise the wear and tear of the roads
• B. to minimise the snow fall
• C. to minimise pollution
• D. to minimise the accumulation of dust on the road

Hint:

Salts like (textCaCl2) are used as de-icing agents because they produce more ions in solution, leading to greater freezing point depression.

Answer 1

The Correct Option is B

Step 1: Identify the property of calcium chloride. Calcium chloride is a highly soluble salt and acts as a strong electrolyte. When dissolved in water, it dissociates into ions: \[ \text{CaCl}_2 \rightarrow \text{Ca}^{2+} + 2\text{Cl}^- \] Step 2: Effect on freezing point. The presence of ions increases the number of particles in solution, which causes a lowering of freezing point (freezing point depression). Step 3: Application on roads in polar regions. When \(\text{CaCl}_2\) is sprinkled on snowy or icy roads:

It lowers the freezing point of water,
Prevents water from freezing easily,
Helps in melting existing snow and ice.
Step 4: Final conclusion. Thus, calcium chloride is used on roads to minimise snow accumulation.