Excess of Lead from human body can be removed by using which of the following chelating agents?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → EDTA
In chelate therapy, a chelating ligand binds a toxic metal ion into a stable, soluble coordination compound that the body can excrete. EDTA (ethylenediaminetetraacetate), a hexadentate ligand that binds through two N and four O atoms, is used in the treatment of lead poisoning.
Why the other options are incorrect
Option (1) D-Penicillamine — Incorrect. It is used to remove excess copper (and iron) from the body, not lead.
Option (2) DMG — Incorrect. Dimethylglyoxime is an analytical reagent for the detection and estimation of \( \ce{Ni^{2+}} \); it is not used in chelate therapy.
Option (3) Desferrioxime B — Incorrect. It removes excess iron (and copper).
NCERT (2026-27 edition):
Importance and Applications of Coordination Compounds – “… There is growing interest in the use of chelate therapy in medicinal chemistry. An example is the treatment of problems caused by the presence of metals in toxic proportions in plant/animal systems. Thus, excess of copper and iron are removed by the chelating ligands D–penicillamine and desferrioxime B via the formation of coordination compounds. EDTA is used in the treatment of lead poisoning.”