ECHEM WATER HARDNESS pt2

    Cards (17)

    • What is a chemical reaction that takes place between a metal ion and a molecular or ionic entity known as a ligand?
      Complexation
    • What is the central component of a complex compound?
      Metal ion
    • What type of molecules can act as ligands?
      Neutral molecules or ions
    • What is a Lewis base?
      A molecule that donates pairs of electrons
    • What is a chelate or chelating agent?
      A substance that forms multiple bonds to a single metal ion
    • What is the meaning of the prefix "poly" in polydentate ligands?
      Many
    • What is the meaning of the suffix "-dentate" in polydentate ligands?
      Toothlike
    • What is an example of a polydentate ligand?
      Ethylenediaminetetraacetic acid (EDTA)
    • What is the function of EDTA in reducing water hardness?
      It forms bonds with metal ions, removing them from water
    • What are the steps involved in complexometric titration?
      1. Collection of water sample
      2. Titration using EDTA solution
      3. Calculation of number of moles of EDTA used
      4. Calculation of number of moles of metal ions (Ca2+) in the sample
      5. Calculation of concentration of Ca2+ in the sample in mol/L
      6. Conversion of concentration to ppm of CaCO3
    • What is the significance of the 1:1 ratio of EDTA ion to metal ion in the chemical reaction?
      It allows for the calculation of the number of moles of metal ions in the sample
    • What is a ligand?
      A molecular or ionic entity that contains at least one atom with an unshared pair of electrons
    • What types of molecules can act as ligands?
      Ions or neutral molecules
    • Why is EDTA important in water treatment?
      It's used to reduce water hardness by forming bonds with metal ions, removing them from water
    • What is a chelating agent?
      A substance that forms (ring like structure) multiple bonds to a single metal ion
    • Is EDTA biodegradable?
      Yes, but the process is considered slow
    • What are the environmental concerns related to EDTA?
      It produces CO2 and has a wide range of applications that may impact the natural environment
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