Statistics and Classical analysis

Question 1

What kind of chelate is EDTA

Answer 1

EDTA forms a hexadentate chelate, which means it uses 6 donor atoms to bind to a metal ion

Question 2

What type of atoms are involved

Answer 2

four oxygen atoms form the carboxylate group (_COO-) and two amine groups form the groups (-NH). these atoms create a very stable complex by providing a lone pair of electrons to form coordination bonds with metal ions

Question 3

why is pH control important in EDTA titrations

Answer 3

EDTA needs to be fully deprotonated to bind to metal ions. The optimal pH is around 10 which ensures that the EDTA is active and the metal ions stay soluble. the buffer maintains consistent pH for effective chelation.

Question 4

what is a suitable indicator for EDTA

Answer 4

a suitable indicator would be eriochrome black T

Question 5

what is the mode of action for the erichrome black T

Answer 5

the initial colour when erichrome black T binds to metal ions such as mg2+ and ca2+, it forms a weak metal indicator complex that is red. When all the free metals (ca2+ and mg2+) are taken up by EDTA, it takes all the remaining metals from the indicator leaving it uncomplexed and changing it to blue at end-point.

Question 6

primary standard

Answer 6

is a highly pure and stable substance used to find the concentration of a solution in titrations.