If `4 g NaOH` are dissolved in `100 mL` of aqueous solution, what will be the differnce in its normality and molarity?

Explanation

To solve the problem of finding the difference between normality and molarity of a solution containing 4 g of NaOH dissolved in 100 mL of water, we can follow these steps:

### Step 1: Calculate the Molar Mass of NaOH
The molar mass of NaOH can be calculated by adding the atomic masses of sodium (Na), oxygen (O), and hydrogen (H):
- Sodium (Na) = 23 g/mol
- Oxygen (O) = 16 g/mol
- Hydrogen (H) = 1 g/mol

**Molar Mass of NaOH = 23 + 16 + 1 = 40 g/mol**

### Step 2: Calculate the Number of Moles of NaOH
Using the formula for moles:
\[ \text{Moles of NaOH} = \frac{\text{mass}}{\text{molar mass}} = \frac{4 \text{ g}}{40 \text{ g/mol}} = 0.1 \text{ moles} \]

### Step 3: Calculate the Volume of the Solution in Liters
Since the volume of the solution is given in mL, we need to convert it to liters:
\[ \text{Volume in liters} = \frac{100 \text{ mL}}{1000} = 0.1 \text{ L} \]

### Step 4: Calculate the Molarity of the Solution
Molarity (M) is defined as the number of moles of solute per liter of solution:
\[ \text{Molarity} = \frac{\text{moles of solute}}{\text{volume of solution in L}} = \frac{0.1 \text{ moles}}{0.1 \text{ L}} = 1 \text{ M} \]

### Step 5: Calculate the Normality of the Solution
Normality (N) for NaOH, which is a monobasic base (it provides one hydroxide ion per molecule), is equal to its molarity:
\[ \text{Normality} = \text{Molarity} = 1 \text{ N} \]

### Step 6: Find the Difference Between Normality and Molarity
Since both normality and molarity are equal in this case:
\[ \text{Difference} = \text{Normality} - \text{Molarity} = 1 \text{ N} - 1 \text{ M} = 0 \]

### Final Answer
The difference between normality and molarity of the NaOH solution is **0**.

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