Industrial Information

Sodium hydroxide, Chloride and Carbonate are among the most important industrial chemicals associated with this Group. Sodium hydroxide is produced by the electrolysis of saturated brine in a cell with steel cathodes and titanium anodes. Sodium Carbonateis made by the Solvay Process, in which soluble Sodium Chloride is converted into insoluble Sodium Hydrogen Carbonate and filtered off, then heated to produce the Carbonate. However, the principal by-product of this process is calcium Chloride, and its deposition in rivers causes environmental concern. The Solvay Process is therefore gradually being replaced by the purification of Sodium Carbonate from minerals.

2. Other bioactive metals

Near 75% of all known chemical elements are metals. Among them there is a series of biologically active macro- and micronutrients (see Table 19).

Table 19. Characteristics of main bioactive metals

Element	Period	Group	Possible Oxidation numbers	Chemical properties
Mg	3	2A	0, +2	Weak amphoteric metal
K	4	1A	0, +1	Typical alkali metal
Ca	4	2A	0, +2	Alkali-Earth Metal
Mn	4	7B	0, +2, +3, +4, +5, +7	Transition metal
Fe	4	8B	0, +2, +3, +6	Transition metal
Co	4	8B	0, +2, +3, +6	Transition metal
Cu	4	1B	0, +1, +2	Transition metal
Zn	4	2B	0, +2	Transition metal
Al	3	3A	0, +1, +3	Amphoteric metal

All bioactive metals depending on its function for plant, animals or human body may be divided into macro-, micronutrients and toxicants (see Table 20).

Table 20. Characteristic of biological function

Element	Biological function
Mg	Included in Chlorophilium
K	Macronutrient for plant nutrition, needed for cell water balance and transparency of membranes
Ca	Macronutrient for plant and human nutrition, takes part in synthesis of proteins
Mn	Micronutrient, takes part in Redox processes. In excess - toxicant
Fe	Micronutrient, needed for processes of breathing and photosynthesis; includes in hemoglobin
Co	Micronutrient, included coferments (for example Vitamin B12 - cobalt ammine). In excess - toxicant
Cu	Irreplaceable micronutrient. In excess - toxicant
Zn	Micronutrient. In excess - toxicant

It is important to know the principles of interaction of metals with different types of acids (see Table 21).

Table 21. Interaction acids-oxidizing agents with metals

Formula of acid	Metals		Notes
	Active: The Alkali, The Alkali-Earth, Mg, Zn	Heavy with low activity
	Scheme of products
H2SO4 (conc.)	Sulfate + S + H2O or Sulfate + H2S + H2O	Sulfate + SO2 + H2O	Fe is immunized by acid
HNO3 (conc.)	Nitrate + N2O + H2O	Nitrate + NO2 + H2O	Not reacts with Au, Pt, Rh, Ir, Ti, Ta; Al, Fe, Co, Ni, Cr are immunized by acid
HNO3 (diluted)	Nitrate + N2 + H2O or Nitrate + NH4NO3+ H2O	Nitrate + NO + H2O	Fe and Sn forms NH4NO3

PRACTICE PROBLEMS

1. Characterize general features of metals atoms.

2. Draw the diagrams of electron redistribution and put the coefficients in the equations of the following reactions and characterize metal properties in these reactions:

Ca + H₂O →

Mn + H₂SO₄ (conc.) →

Zn + CuSO₄ →

Al + Fe₂O₃ →

LABORATORY TRAINING

Experiment 1. Replacing of metals

Put into two test tubes 5-6 drops of CuSO₄ and Pb (CH₃COO) ₂ solutions and add in each tube one granule of free Zinc. 5-10 min. later register how color of Zinc granule is changed. Write the reactions.

Experiment 2. Qualitative test of K⁺ in salts or fertilizers

Fill test-tube with 3-4 drops of Potassium salt solution and add 2-3 drops of Na₃[Co(NO₂)₆]. Form yellow precipitate NaK₂[Co(NO₂)₆]. Write the reactions of precipitate formation.

Experiment 3.Change of Calcium Phosphates solubility

Add 2-3 drops of Na₂HPO₄ solution to 1-2 drops of CaCl₂ Solution. Why was precipitate formed?

Add by drops Solution of Phosphorus acid to precipitate until to total dissolving. Write the reactions of precipitate formation and dissolving.

Experiment 4. Oxidizing property of Cu⁺² ions

Add 2-3 drops of KI solution to 3-4 drops of CuSO₄ solution. Observe formation of CuI precipitate and Iodine I₂ isolation. Write the reaction.

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