Nickle chloride Experiment

Aim: To determine unknown concentration of nickel chloride from the given solution.

Reference: Svehla, G. Vogel’s Qualitative Inorganic Analysis, 7th ed. Pearson Education India. 2008. p. 143.

Requirements: Nickle chloride powder, Concentrated ammonia solution, distilled water, pipette, volumetric flask etc.

Principle: Nickle on reaction with aqueous ammonia or other hydroxides, produces green coloured precipitates of Ni(OH)2.

Ni+2 + 2OH → Ni(OH)2

The precipitate is insoluble in other hydroxides, but in presence of excess ammonia precipitates gets dissolved completely.

Ni(OH)2↓ + 6NH3 → [Ni(NH3)6]+2 + 2OH

Ni(OH)2↓ + 6NH4+ + 4OH → [Ni(NH3)6]+2 + 6H2O

The resulting solution have clear blue colour due to formation of a complex [Ni(NH3)6]+2.

Procedure:

  • Weigh accurately 2 g of nickel chloride powder and dissolve it in distilled water up to 100 mL (2% w/v solution of nickel chloride). This solution is considered as stock solution of nickel chloride.
  • From, the stock solution of nickel chloride, pipette out various aliquots to have final concentration, 2, 4, 6, 8 and 10 mg/mL nickel chloride. The final volume of solution to be prepared is 10 mL.
  • Use the following table to prepare different dilutions for the purpose of standard curve of nickel chloride.
Flask No. Solution Volume of stock solution taken Volume of ammonia added Volume of distilled water added Total volume
1 2 mg/ mL Std. NiCl2 1 mL 2 mL 7 mL 10 mL
2 4 mg/ mL Std. NiCl2 2 mL 2 mL 6 mL 10 mL
3 6 mg/ mL Std. NiCl2 3 mL 2 mL 5 mL 10 mL
4 8 mg/ mL Std. NiCl2 4 mL 2 mL 4 mL 10 mL
5 10 mg/ mL Std. NiCl2 5 mL 2 mL 3 mL 10 mL
Unknown Unknown 3 mL unknown 2 mL 5 mL 10 mL
  • Scan the 6 mg/mL std. solution between 200-800 nm, to find out the absorbance maxima by taking mixture of 2 mL ammonia and 8 mL distilled water as a blank.
  • Measure the absorbance of the remaining solutions including unknown at the absorption maxima.
  • Plot the graph of absorbance Vs. concentration. Find out the equation of straight line.
  • Find out the unknown concentration of nickel chloride directly from the graph as well as using equation of straight line.

Result: The given unknown solution contains _______ % w/v of nickel chloride.

CE-I Stars

Dear Students….. Congratulations for Securing more than 15 marks out of 20.

Aashu Gupta – 17 Marks

Angana Shashtri – 17 Marks

Milind Patel – 16 Marks

Shivangi Agrawal – 18 Marks

Reference Format

Dear students, as per following format, you need to write the reference in your journal.

For pharmacopoeia,

 

Indian Pharmacopoeia. Indian Pharmacopoeial Commission on Behalf of Govt. of India- Ministry of Health and Family Welfare; 2010. p. 849.

For book,

Vogel HG, editor. Drug Discovery and Evaluation. 2nd ed. Germany: Springer Berlin Heidelberg; 2002. p.