Question

NiO > NiSO4 > Ni(OH)2 > NiCl2

Answer 1

Ответ:

1. 2Ni + O₂ = 2NiO

2. NiO + H₂SO₄ = NiSO₄ + H₂O

3.Ni + H2O = Ni(OH)2

4.Ni+Cl2=NiCl2

Answer 2

The given sequence represents the increasing order of solubility for different nickel compounds.

NiO (nickel(II) oxide) is least soluble in water among the compounds mentioned. It is sparingly soluble in water and forms a basic solution due to its reaction with water to produce nickel(II) hydroxide.

NiSO4 (nickel(II) sulfate) is more soluble than NiO. It dissolves readily in water to form an aqueous solution. Nickel(II) sulfate is a strong electrolyte and dissociates completely into nickel(II) ions (Ni2+) and sulfate ions (SO4²-) in solution.

Ni(OH)2 (nickel(II) hydroxide) is more soluble than NiSO4. It is a moderately soluble compound that forms a colloidal suspension in water. It can dissolve further with the addition of acid, forming the soluble nickel(II) ion.

NiCl2 (nickel(II) chloride) is the most soluble among the mentioned compounds. It readily dissolves in water to form an aqueous solution. Nickel(II) chloride is a strong electrolyte and dissociates completely into nickel(II) ions (Ni2+) and chloride ions (Cl-) in solution.

Therefore, the solubility order from least soluble to most soluble is: NiO < NiSO4 < Ni(OH)2 < NiCl2