Get Answers to all your Questions

header-bg qa

Which one of the following statements is not true?

  • Option 1)

    Dissolved oxygen (DO) in cold water can reach a concentration upto 10 ppm.

  • Option 2)

    Clean water would have a BOD value of 5ppm

  • Option 3)

    Fluoride deficiency in drinking water is harmful.Soluble fluoride os often used to bring its concentration upto 1 ppm

  • Option 4)

    When the pH of rainwater is higher than 6.5, it is called acid rain

 

Answers (1)

best_answer

As learnt in

Acid rain -

Rainfall and other precipitation with a pH of less than 5.6 . Acidic components, sulphuric acid and nitric acid,
are emitted into the atmosphere from thermal power plants, industries, automobiles.

- wherein

2SO_{2}(g)+O_{2}(g)+2H_{2}O(l)
ightarrow 2H_{2}SO_{4}(aq)

4NO_{2}(g)+O_{2}(g)+2H_{2}O(l)
ightarrow 4HNO_{3}(aq)

 

 


Option 1)

Dissolved oxygen (DO) in cold water can reach a concentration upto 10 ppm.

This option is incorrect

Option 2)

Clean water would have a BOD value of 5ppm

This option is incorrect

Option 3)

Fluoride deficiency in drinking water is harmful.Soluble fluoride os often used to bring its concentration upto 1 ppm

This option is incorrect

Option 4)

When the pH of rainwater is higher than 6.5, it is called acid rain

This option is correct

Posted by

Plabita

View full answer