Nickel(II) reacts with dimethylglyoxime [C4H6(NOH)2] to form a neutral coordination complex. The formation of the red chelate occurs quantitatively in an aqueous solution at pH 5 to 9. Usually, citric acid is added to lower the interference of other ions like iron.
Similar to Aim: Estimate the amount of Nickel present in a given solution as bis(dimethylglyoximato)nickel(II) gravimetrically by counterpoise filter paper.
Similar to Aim: Estimate the amount of Nickel present in a given solution as bis(dimethylglyoximato)nickel(II) gravimetrically by counterpoise filter paper. (20)
Aim: Estimate the amount of Nickel present in a given solution as bis(dimethylglyoximato)nickel(II) gravimetrically by counterpoise filter paper.
1. SHREE MALLIKARJUN COLLEGE SYBSC
SAFETY: Refer to MSDS of nickel nitrate, nickel chloride, dimethylglyoxime, citric acid, ethanol
-Dr. Mithil S. Fal Desai
Aim: Estimate the amount of Nickel present in a given solution as
bis(dimethylglyoximato)nickel(II) gravimetrically by counterpoise filter paper.
Chemicals: Nickel salt (nickel nitrate, nickel chloride), dimethylglyoxime, citric acid, ethanol.
Apparatus: Beaker, conical flask, funnel, Whatman 41, glass rod with policemen, water bath,
oven.
Theory: Nickel(II) reacts with dimethylglyoxime [C4H6(NOH)2] to form a neutral coordination
complex. The formation of the red chelate occurs quantitatively in an aqueous solution at pH 5
to 9. Usually, citric acid is added to lower the interference of other ions like iron.
Reaction
Ni2+
(aq)+ 2C4H8N2O2(aq) [Ni(C4H7N2O2)2](s) + 2H+
(aq)
Procedure:
1) Pipette out 25 mL of nickel solution in a 100 mL beaker and add 5 mL of 0.5% citric acid
solution with constant stirring.
2) Add 25 mL of 1% dimethylgloxime solution to the beaker (red color precipitate is formed)
and keep the beaker along with precipitate to digest in a water bath for 30 min.
3) After 30 min, cool the solution and add 1-2 mL of DMG solution along the sides of the beaker
and check for complete precipitation.
4) Take 2 filter papers having the same weight and place them in the same funnel. (If the weight
of the two filter papers is not equal cut the top edge of filter paper to adjust the weight.)
5) Transfer the precipitate to the filter paper and wash the precipitate with distilled water until
the filtrate shows a negative chloride test. Finally, add 5-10 mL of alcohol to remove the excess
water.
6) Keep the funnel along with filter paper in the oven at 80-90 0C for around 45 min.
7) After 45 min, cool the filter papers in a desiccator and then weigh both the filter papers with
(W1) and without precipitate (W2). (To get the constant weights to repeat the step 6 and 7)
8) The difference in weight quantitatively corresponds to Ni-DMG complex formed.
Observation
Table 1.
Constant
weight of filter
paper without
precipitate
“W1’ (g)
Constant
weight of filter
paper with
precipitate
“W2’ (g)
Weight of
Ni-complex
‘A’=W2 – W1
(g)
Molecular
weight of
Complex
‘B’ (g)
Atomic weight
Ni ‘C’(g)
Amount of Ni
in 25 mL
‘x' = A* C/B
(g)
58.71
Result: Amount of nickel in 500 mL is ______g.
Note: To get a better result G4 crucible shall be used.
![SHREE MALLIKARJUN COLLEGE SYBSC
SAFETY: Refer to MSDS of nickel nitrate, nickel chloride, dimethylglyoxime, citric acid, ethanol
-Dr. Mithil S. Fal Desai
Aim: Estimate the amount of Nickel present in a given solution as
bis(dimethylglyoximato)nickel(II) gravimetrically by counterpoise filter paper.
Chemicals: Nickel salt (nickel nitrate, nickel chloride), dimethylglyoxime, citric acid, ethanol.
Apparatus: Beaker, conical flask, funnel, Whatman 41, glass rod with policemen, water bath,
oven.
Theory: Nickel(II) reacts with dimethylglyoxime [C4H6(NOH)2] to form a neutral coordination
complex. The formation of the red chelate occurs quantitatively in an aqueous solution at pH 5
to 9. Usually, citric acid is added to lower the interference of other ions like iron.
Reaction
Ni2+
(aq)+ 2C4H8N2O2(aq) [Ni(C4H7N2O2)2](s) + 2H+
(aq)
Procedure:
1) Pipette out 25 mL of nickel solution in a 100 mL beaker and add 5 mL of 0.5% citric acid
solution with constant stirring.
2) Add 25 mL of 1% dimethylgloxime solution to the beaker (red color precipitate is formed)
and keep the beaker along with precipitate to digest in a water bath for 30 min.
3) After 30 min, cool the solution and add 1-2 mL of DMG solution along the sides of the beaker
and check for complete precipitation.
4) Take 2 filter papers having the same weight and place them in the same funnel. (If the weight
of the two filter papers is not equal cut the top edge of filter paper to adjust the weight.)
5) Transfer the precipitate to the filter paper and wash the precipitate with distilled water until
the filtrate shows a negative chloride test. Finally, add 5-10 mL of alcohol to remove the excess
water.
6) Keep the funnel along with filter paper in the oven at 80-90 0C for around 45 min.
7) After 45 min, cool the filter papers in a desiccator and then weigh both the filter papers with
(W1) and without precipitate (W2). (To get the constant weights to repeat the step 6 and 7)
8) The difference in weight quantitatively corresponds to Ni-DMG complex formed.
Observation
Table 1.
Constant
weight of filter
paper without
precipitate
“W1’ (g)
Constant
weight of filter
paper with
precipitate
“W2’ (g)
Weight of
Ni-complex
‘A’=W2 – W1
(g)
Molecular
weight of
Complex
‘B’ (g)
Atomic weight
Ni ‘C’(g)
Amount of Ni
in 25 mL
‘x' = A* C/B
(g)
58.71
Result: Amount of nickel in 500 mL is ______g.
Note: To get a better result G4 crucible shall be used.](https://image.slidesharecdn.com/determinationofni-dmg-210421045100/85/Aim-Estimate-the-amount-of-Nickel-present-in-a-given-solution-as-bis-dimethylglyoximato-nickel-II-gravimetrically-by-counterpoise-filter-paper-1-320.jpg)
