Case 1 : Common edible salt, NaCl Sodium Chloride ) obtained from seawater or from lakes contains many impurities such as sulphates of sodium and magnesium along with chlorides of calcium and magnesium. The chlorides of these metals are particularly undesirable being deliquescent in nature. A saturated solution of salt in a minimum quantity of water is prepared and insoluble impurities are filtered off. HCL gas is then passed through the saturated solution and the crystals of pure NaCl separate out. the soluble impurities remain in the solution. Pure crystals of NaCl are filtered, washed and dried.
Choose the correct statement:

Options

A. Pure NaCl is hygroscopic in nature by itself
B. Pure NaCl is soluble in alcohol
C. NaCl shows hygroscopic properties only due to impurities
D. NaCl is a brown crystalline solid

Answer

To solve the question regarding the properties of pure sodium chloride (NaCl) and its behavior in the presence of impurities, we will analyze each statement provided in the question step by step.

### Step 1: Analyze the first statement
**Statement:** Pure NaCl is hygroscopic in nature by itself.

**Analysis:**
- Hygroscopic substances are those that can absorb moisture from the environment.
- Pure NaCl does not absorb moisture on its own; it only becomes hygroscopic when impurities are present.
- Therefore, this statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement:** Pure NaCl is soluble in alcohol.

**Analysis:**
- Sodium chloride (NaCl) is an ionic compound, and it is generally soluble in polar solvents like water.
- Alcohols, such as methanol (CH3OH), are less polar compared to water.
- According to the principle "like dissolves like," NaCl will not dissolve well in alcohol due to its lower polarity.
- Thus, this statement is also **incorrect**.

### Step 3: Analyze the third statement
**Statement:** NaCl shows hygroscopic property only due to impurities.

**Analysis:**
- As discussed earlier, pure NaCl does not absorb moisture unless impurities are present.
- The presence of these impurities allows NaCl to exhibit hygroscopic properties.
- Therefore, this statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement:** NaCl is a brown crystalline solid.

**Analysis:**
- Pure NaCl is actually a colorless crystalline solid.
- The statement claiming it is brown is incorrect.
- Hence, this statement is **incorrect**.

### Conclusion
After analyzing all the statements, the only correct statement is that NaCl shows hygroscopic property only due to impurities.

### Final Answer:
The correct statement is: **NaCl shows hygroscopic property only due to impurities.**

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