If soap has high alkali content it irritates skin. How can the amount of excess alkali be determined ? What can be the source of excess alkali ?

Explanation

### Step-by-Step Solution:

1. **Understanding the Problem**:
- The question states that soap with high alkali content can irritate the skin. We need to determine how to measure the excess alkali and identify its source.

2. **Determining Excess Alkali**:
- To quantify the excess alkali in soap, we can use **acid-base titration**. This method allows us to measure the amount of alkali present in the soap solution by neutralizing it with a standard acid.

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