Correct Answer - A
`[H_(2)EDTA]^(2-)+Mg^(2+) rarr [Mg-EDTA ]^(2)+2H^(+)`
(i) In this complex, four donor sites are occupied by oxygen and two donor sites are occupied by hydrogen.
(ii) This complex is six coordinated.
(iii) Complex `[Mg-EDTA]^(2-)` is colourless.
(iv) Increase in `[H^(+)]` decreases pH of the solution