When 0.01 moles of NaOH are added to 1 litre of a buffer solution , its pH changes from 4.745 to 4.832. The buffer capacity is

Options

A. 0.0115
B. 11.5
C. 0.115
D. None

Answer

To find the buffer capacity of the solution after adding 0.01 moles of NaOH, we can follow these steps:

### Step 1: Understand the concept of buffer capacity
Buffer capacity is defined as the amount of acid or base that can be added to a buffer solution before a significant change in pH occurs. It can be calculated using the formula:

\[ \text{Buffer Capacity} = \frac{\text{Number of moles of strong base (or acid)}}{\text{Change in pH}} \]

### Step 2: Identify the given values
- Number of moles of NaOH added = 0.01 moles
- Initial pH = 4.745
- Final pH = 4.832

### Step 3: Calculate the change in pH
To find the change in pH, subtract the initial pH from the final pH:

\[ \text{Change in pH} = \text{Final pH} - \text{Initial pH} = 4.832 - 4.745 = 0.087 \]

### Step 4: Substitute the values into the buffer capacity formula
Now, we can substitute the values into the buffer capacity formula:

\[ \text{Buffer Capacity} = \frac{0.01 \text{ moles}}{0.087} \]

### Step 5: Perform the calculation
Now, we perform the division:

\[ \text{Buffer Capacity} = \frac{0.01}{0.087} \approx 0.1149 \]

### Step 6: Round the answer
Rounding 0.1149 gives approximately 0.115.

### Final Answer
Thus, the buffer capacity is approximately **0.115**.