Procedure

• The given nickel solution is made up to 100 mL in a standard measuring flask.
• 20 mL of solution is pipetted into a 250 mL beaker.
• About 5 mL 1:1 HCl is added and diluted to 150 mL.
• The solution is heated to 70–80 °C. 25 mL of 1% dimethyl glyoxime in alcohol is added, immediately followed by dilute ammonia solution dropwise until it strongly smells of ammonia.
• The solution containing the precipitate is heated in a water bath for 30 minutes.
• The precipitate is allowed to stand for an hour.
• Filter the solution through a previously weighed sintered glass crucible.
• The precipitate is washed with cold water to free chloride.
• The crucible is placed in a dry 100 mL beaker and heated in the air oven at 110–120 °C for 1 hour.
• It is cooled in a desiccator and weighed. Repeat drying until constant weight is obtained.

Calculation:

Mass of sintered glass crucible = a g

Mass of sintered glass crucible + nickel complex = b g

Mass of dimethyl glyoxime nickel complex = (b − a) g

288.69 g of nickel complex contains 58.69 g of nickel.

$$\frac{58.69\times (b\times a)}{288.69}$$

Therefore, Mass of nickel in the whole of the given solution

$$\frac{58.69\times (b\times a)\times 5}{288.69}$$