Question

Match the correct term with the description:

Terms: Metal ion indicator, acid-base indicator, auxiliary complexing agent, direct, back,

displacement, indirect, and masking agent.

Titration where anions that precipitate with metal ions can be measured. ___________

Titration where the analyte is titrated with standard EDTA. _______________

Ligand that is added to keep some component of the analyte from reacting

with EDTA. _____________

Compound that changes color when bound to a metal ion. _______________

Titration where the analyte is treated with a metal-EDTA complex. _________

Compound that has a different color for each protonated state. _______________

Ligand added to keep metal ions from forming solid hydroxides. _______________

Titration where an excess of EDTA is added to the analyte. _______________

Answer 1

I) Titration where anions that precipitate with metal ions can be measured. Indirect Titration

II) Titration where the analyte is titrated with standard EDTA. Direct titration

III) Ligand that is added to keep some component of the analyte from reacting with EDTA. Masking Agent : Masking agent helps by preventing or masking chemical species which can hinder the analyte from reacting with EDTA (in this case).

IV) Compound that changes color when bound to a metal ion. Metal ion indicator

V) Titration where the analyte is treated with a metal-EDTA complex. displacement titration : It is used when there is not a indicator for detection of analyte. Analyte displaces the second metal and then this second metal is titrated.

VI) Compound that has a different color for each protonated state. acid-base indicator

VII) Ligand added to keep metal ions from forming solid hydroxides. auxiliary complexing agent : Auxillary agents helps in the case of metal ions, preventing them to form hydroxides but release metal ion in the presence of EDTA.  

VIII) Titration where an excess of EDTA is added to the analyte. back titration : In this kind of titration, known amount of EDTA solution is added which can be back titrated on completion of the reaction. Then, the EDTA solution is back titrated with standard solutions.