In the iodometric estimation in the laboratory which process is involved?

Options

A. `Cr_(2)O_(7)^(2-) + H^(+) + I^(-) to 2Cr_(3+) + I_(2)`
`I_(2) + S_(2)O_(3)^(2-) to S_(4)O_(6)^(2-) + I^(-)`
B. `MnO_(4)^(-) + OH^(-) + I^(-) to MnO_(2) + I^(2)`
`I_(2) + S_(2)O_(3)^(2-) to S_(4)O_(6)^(2-) + I^(-)`
C. `MnO_(4)^(-) + OH^(-) + I^(-) to MnO_(2) + I_(2)`
`I_(2) + S_(2) O_(3)^(2-) to S_(4)O_(6)^(2-) + I(-)`
D. `Cr_(2)O_(7)^(2-) + OH^(-) + I^(-) to 2Cr^(3+) + I_(2)`
`I_(2) + S_(2)O_(3)^(2-) to S_(2)O_(6)^(2-) + I^(-)`

Answer

D

Explanation

`Na_(4)(EDTA)`, EDTA is a tetravlent anion