Which of the following has highest pH ?

Options

A. Human saliva
B. Human blood
C. Gastric juice
D. Urine

Answer

To determine which of the given substances has the highest pH, we need to analyze the pH values of each option provided:

1. **Human Saliva**: The average pH of human saliva is approximately 6.7. This indicates that it is slightly acidic.

2. **Human Blood**: The average pH of human blood is around 7.40. This value is slightly above neutral, indicating that it is slightly basic.

3. **Gastric Juice**: The average pH of gastric juice is about 3. This is highly acidic.

4. **Urine**: The average pH of urine is around 6. This also indicates that it is slightly acidic.

Now, let's compare these pH values:

- Human Saliva: 6.7
- Human Blood: 7.40
- Gastric Juice: 3
- Urine: 6

Among these values, the highest pH is that of **Human Blood**, which is 7.40.

**Final Answer**: Human Blood has the highest pH.