Permissible level of nitrate ions in the drinking water is

Options

A. 40 ppm
B. 50ppm
C. 60ppm
D. 70ppm

Answer

To determine the permissible level of nitrate ions in drinking water, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the permissible level of nitrate ions (NO3-) in drinking water, which is a common concern in environmental chemistry due to health implications.

2. **Identify the Options**: The options provided are 40 ppm, 50 ppm, 60 ppm, and 70 ppm. We need to evaluate these options based on established health guidelines.

3. **Refer to Health Guidelines**: According to health and environmental standards, the permissible level of nitrate ions in drinking water is typically set to prevent health risks.

4. **Determine the Correct Value**: The maximum permissible level of nitrate ions in drinking water is generally recognized as 50 mg/L (milligrams per liter), which is equivalent to 50 ppm (parts per million).

5. **Conclude the Answer**: Since the permissible level of nitrate ions in drinking water should not exceed 50 ppm, we conclude that the correct answer is 50 ppm.

### Final Answer:
The permissible level of nitrate ions in drinking water is **50 ppm**.

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