Which of the following is widely used for treating ice on roads, particularly in very cold countries?

Options

A. `CaCl_(2)` is less soluble in `H_(2)O ` than NaCl
B. `CaCl_(2)` is hygroscopic but NaCl is not
C. eutectic mixture of `CaCl_(2)"/"H_(2)O` freezes at `-55^(@)C` while that of `NaCl"/"H_(2)O` freezes at `-18^(@)C`
D. NaCl makes the road slipperty but `CaCl_(2)` does not

Explanation

To solve the question of which compound is widely used for treating ice on roads in very cold countries, we can follow these steps:

### Step 1: Understand the Problem
We need to identify a chemical compound that is effective in melting ice on roads, particularly in cold climates.

**Hint:** Consider the properties of common salts and their freezing point depression capabilities.

### Step 2: Identify Common Compounds Used for Ice Melting
The most commonly used compounds for treating ice on roads are salts. The two primary salts that come to mind are sodium chloride (NaCl) and calcium chloride (CaCl2).

**Hint:** Recall the freezing point depression effect of these salts when dissolved in water.

### Step 3: Compare the Freezing Points
- Sodium chloride (NaCl) lowers the freezing point of water to about -18 degrees Celsius.
- Calcium chloride (CaCl2) lowers the freezing point of water to about -55 degrees Celsius.

**Hint:** Look for the compound that has a lower freezing point when mixed with water, as this will be more effective in melting ice.

### Step 4: Determine the Most Effective Compound
Since CaCl2 has a much lower freezing point compared to NaCl, it is more effective in melting ice at lower temperatures.

**Hint:** Think about the practical applications of these compounds in real-world scenarios, especially in very cold regions.

### Step 5: Conclusion
Based on the comparison, calcium chloride (CaCl2) is the compound widely used for treating ice on roads in very cold countries due to its ability to lower the freezing point of water significantly.

**Final Answer:** The correct option is calcium chloride (CaCl2).

### Summary of Steps:
1. Understand the problem.
2. Identify common compounds used for ice melting.
3. Compare the freezing points of NaCl and CaCl2.
4. Determine which compound is more effective.
5. Conclude with the correct answer.