The normally of `4%` (wt/vol).`NaOH` is:

Options

A. `0.1`
B. `1.0`
C. `0.05`
D. `0.01`

Explanation

To find the normality of a 4% (wt/vol) NaOH solution, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of 4% (wt/vol)**:
- A 4% (wt/vol) solution means there are 4 grams of solute (NaOH) in 100 mL of solution.

2. **Calculate the Number of Moles of NaOH**:
- The molar mass of NaOH (sodium hydroxide) is approximately 40 g/mol.
- To find the number of moles, use the formula:
\[ \text{Number of moles} = \frac{\text{Mass of solute (g)}}{\text{Molar mass (g/mol)}} \]
- Substituting the values:
\[ \text{Number of moles} = \frac{4 \text{ g}}{40 \text{ g/mol}} = 0.1 \text{ moles} \]

3. **Determine the n Factor for NaOH**:
- NaOH dissociates in solution to give one hydroxide ion (OH⁻), so the n factor (the number of equivalents per mole) for NaOH is 1.

4. **Calculate the Number of Equivalents**:
- The number of equivalents can be calculated using the formula:
\[ \text{Number of equivalents} = \text{Number of moles} \times \text{n factor} \]
- Substituting the values:
\[ \text{Number of equivalents} = 0.1 \text{ moles} \times 1 = 0.1 \text{ equivalents} \]

5. **Convert the Volume of Solution to Liters**:
- The volume of the solution is given as 100 mL. To convert this to liters:
\[ \text{Volume in liters} = \frac{100 \text{ mL}}{1000} = 0.1 \text{ L} \]

6. **Calculate the Normality**:
- Normality (N) is defined as the number of equivalents of solute per liter of solution:
\[ N = \frac{\text{Number of equivalents}}{\text{Volume of solution in liters}} \]
- Substituting the values:
\[ N = \frac{0.1 \text{ equivalents}}{0.1 \text{ L}} = 1 \text{ N} \]

### Final Answer:
The normality of the 4% (wt/vol) NaOH solution is **1 N**.

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