Calculate the pH of following solutions.
`N//10 NaOH`

Answer

To calculate the pH of a \( \frac{N}{10} \) NaOH solution, follow these steps:

### Step 1: Understand the Normality and Molarity
Given that the solution is \( \frac{N}{10} \) NaOH, we can convert normality to molarity. Since NaOH is a strong base that dissociates completely in water, its normality is equal to its molarity.

\[ \text{Normality (N)} = 0.1 \, N \quad \text{(which is equivalent to 0.1 mol/L)} \]

### Step 2: Determine the Concentration of Hydroxide Ions
For NaOH, which dissociates completely in water:

\[ \text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^- \]

The concentration of hydroxide ions \([\text{OH}^-]\) is equal to the molarity of NaOH:

\[ [\text{OH}^-] = 0.1 \, M \]

### Step 3: Calculate the pOH
To find the pOH, we use the formula:

\[ \text{pOH} = -\log[\text{OH}^-] \]

Substituting the concentration of hydroxide ions:

\[ \text{pOH} = -\log(0.1) = -\log(10^{-1}) = 1 \]

### Step 4: Calculate the pH
Using the relationship between pH and pOH:

\[ \text{pH} + \text{pOH} = 14 \]

Substituting the value of pOH:

\[ \text{pH} = 14 - \text{pOH} = 14 - 1 = 13 \]

### Final Answer
The pH of the \( \frac{N}{10} \) NaOH solution is **13**.

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