JEE Main20241 Feb 2024Evening ShiftChemistryCoordination CompoundsActual
Given below are two statements : Statement (I) : Dimethyl glyoxime forms a six membered covalent chelate when treated with NiCl 2 solution in presence of NH 4 OH . Statement (II) : Prussian blue precipitate contains iron both in + 2 and + 3 oxidation states. In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- AStatement I is false but Statement II is true
- BBoth Statement I and Statement II are true
- CBoth Statement I and Statement II are false
- DStatement I is true but Statement II is false
Correct answer
A. Statement I is false but Statement II is true
Step-by-step solution
According to Statement I, On addition of dimethylglyoxime (DMG) to nickel ion solution and on adding little bit of ammonia to make solution basic, it will give a red precipitate. This is a very specific test for nickel + 2 cation. The reaction is as follows, Ni 2 + + NH 4 OH + dmg → 2 hydrogen bonded chelatesare formed. According to Statement II, III Fe 4 II Fe CN 6 3 Prussian Blue IN this complex Fe is at + 3 as well as + 2 oxidation state. Where ionisation sphere is Fe 3 + and coordination sphere has Fe 2 + Hence