21. SALTS. CLASSIFICATION. RECEIVING. PROPERTIES.

Salts - the complex substances consisting of atoms of metals of metals (hydrogen sometimes enters) and acid radicals.

Classification of salts.

Names of salts.

Acid radical (anion)	Name of salt
Cl-	chloride
F-	fluoride
NO3-	nitrate
NO2-	nitrite
S2-	sulfide
SO32-	sulfite
SO42-	sulfate
CO32-	carbonate
SiO32-	silicate
PO43-	phosphate
CN-	cyanide
NCS-	thiocyanate
ClO-	hypochlorite
ClO2-	chlorite
ClO3-	chlorate
ClO4-	perchlorate

If metal has variable valency, then it is specified after chemical element in the Roman figure bracketed. For example _CuSO4-copper sulfate (II).

Receiving salts.

1. With use of metals	metal + nonmetal	Mg+Cl2=MgCl2
	metal + acid	Zn+2HCl=ZnCI2+H2
	metal + salt	Fe+CuSO4=FeSO4+Cu
2. With use of oxides	main oxide + acid	CaO+2HCl=CaCl2+H2O
	acid oxide + basis	CO2+Ca(OH)2=CaCO3+H2O
	acid + the main oxides	CaO+CO2=CaCO3
	the main + amphoteric oxides	Al2O3+CaO=Ca(AlO2)2
3. Neutralization reaction	acid + basis	H2SO4+2NaOH=Na2SO4+2H2O
4. From salts	salt + salt	AgNO3+NaCl=AgCl+NaNO3
	salt + alkali	CuSO4+2NaOH=Cu(OH)2+Na2SO4
	salt + acid	Na2CO3+2HCl=2NaCl+H2O+CO2
Acid salts receive in the same ways, as averages, but at other molar ratios (at excess of acid)
NaOH+H2SO4=NaHSO4+H2O
Basic salts are formed at interaction of some salts with alkalis (at excess of alkali)
ZnCl2+NaOH=ZnOHCl+NaCl

Chemical properties of salts.

Decomposition when calcinating	CaCO3=CaO+CO2
Salt + metal	Fe+CuSO4=FeSO4+Cu
Salt + salt	AgNO3+NaCl=AgCl+NaNO3
Salt + alkali	CuSO4+2NaOH=Cu(OH)2+Na2SO4
Salt + acid	Na2CO3+2HCl=2NaCl+H2O+CO2

 

  

 

---

21

---