|áOxidation state||áName||áFormula||áExample compounds|
|á-1||áchlorides||áCl?||ionic chlorides, organic chlorides, hydrochloric acid|
|á+1||áhypochlorites||áClO?||sodium hypochlorite, calcium hypochlorite|
|á+5||áchlorates||áClO3?||sodium chlorate, potassium chlorate, chloric acid|
|á+7||áperchlorates||áClO4?||potassium perchlorate, perchloric acid, magnesium perchlorate organic perchlorates, ammonium perchlorate, dichlorine heptoxide|
hydrogen CHLORIDE. Pure HCl is a colorless gasáwith a repugnant smell, m.p. = -85.1ţĐ. It is easily liquefied at high pressure. HCl is soluble in water well: at 20 ţă 2.5 volumes of HCl can be dissolved in 1 volume of H2O. Aqueous HCl solution has nameáhydrochloric (Historically, is also called muriatic)acid. HCl with water forms azeotropic boiling mixture, that contains 20.24% HCl. The commercial concentrated HCl contains 37% HCl, it has a density of r = 1.19 g / cm3. Hydrochloric acid belongs to the series of very strong acids.
Curious enough for water solution it is easy to find the approximate HCl percentage, simply multiplying on 2 the value after comma of the decimal fractional part of its density value. For example, at the density of 1.19 g / cm3áthe percentage HCl will be equal 19.2 = 38%. Consequently, and vice versa, knowing the percentage HCl in hydrochloric acid, it is possible to estimate approximately its density.
By preparation 1.184 N solution of HCl it is convenient to prepare medium with pH = 0 (at 25 oC).
Pure: H2 + Cl2 = 2HCl
Technical purity: In great amount HCl is obtained as a by-product of chlorination of organic compounds:
RH + Cl2 = R-Cl + HCl
where R is the organic radical.
Example: CH4 + Cl2 = CH3Cl + HCl
NaCl + H2SO4 = HCl + NaHSO4 on cold
á2NaCl + H2SO4 = 2HCl + Na2SO4 at heating