Skip to content
Skip to main content

About this free course

Download this course

Share this free course

What chemical compounds might be present in drinking water?
What chemical compounds might be present in drinking water?

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Summary of Section 2

  • Nitrogen in the atmosphere is relatively inert due to its strong triple bond.
  • Bacteria in the roots of plants fix nitrogen from the atmosphere.
  • Industrially the Haber-Bosch process fixes nitrogen:
     
    N2(g) + 3H2(g) = 2NH3(g)
    (Equation 8)
  • Nitric acid is produced by the Ostwald process:
     
    four NH sub three left parenthesis g right parenthesis prefix plus of five cap o sub two left parenthesis g right parenthesis equals four NO left parenthesis g right parenthesis prefix plus of six cap h sub two cap o left parenthesis g right parenthesis
    (Equation 11)
    NO left parenthesis g right parenthesis prefix plus of one divided by two times cap o sub two left parenthesis g right parenthesis equals NO sub two left parenthesis g right parenthesis
    (Equation 12)
    three NO sub two left parenthesis g right parenthesis prefix plus of cap h sub two cap o left parenthesis l right parenthesis equals two HNO sub three left parenthesis aq right parenthesis plus NO left parenthesis g right parenthesis
    (Equation 13)

    Nitric acid is then used to make ammonium nitrate fertiliser.

  • Excess levels of nitrate, NO3−, in water can result in eutrophication in the environment. While high levels of nitrate in drinking water are dangerous for infants because the nitrate can be reduced to nitrite in the body which may interfere with oxygen binding by haemoglobin.
  • Arsenic levels in natural waters correspond to the oxoanions arsenite, AsO33-, and arsenate, AsO43-.
  • Excess nitrate or arsenate can be removed from water by ion-exchange chromatography.
  • Fluoride is important in dental health but if levels are too high in drinking water then health problems may result.