Question

Which one of the following statement s in not true?

• A. Clean water would have a BOD value of 6 ppm.
• B. Fluoride deficiency in drinking water is harmful. Soluble fluoride is used to bring its concentration upto 1ppm.
• C. When the pH of rain water is higher than 6.5, it is called acid rain.
• D. Dissolved Oxygen (DO) in cold water can reach a concentration upto 10 ppm.

Answer 1

The correct option is C When the pH of rain water is higher than 6.5, it is called acid rain.

When pH of ran water drops below 5.6 it is called acid rain.