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The Periodic Table

The Halogens - Hydrogen Halides.

The halogens will react with hydrogen to form hydrogen halides.

Hydrogen will react with chlorine to form hydrogen chloride.
hydrogen + chlorine     hydrogen chloride.
H_2(g)    +     Cl_2(g)                2HCl_(g)

For properties of HCl_(g) see test for HCl gas.
For the structure of HCl_(g) see structure of HCl.

Hydrogen chloride is very, very soluble in water.
It dissolves to form hydrochloric acid.

hydrogen chloride + water     hydroxonium ion +  chloride ion.
HCl_(g)    +     H₂O_(l)                H₃O⁺_(aq)    +      Cl^-_(aq)

The hydroxonium ion, H₃O⁺, (often written just as H⁺, hydrogen ion)
is an acid in water  -  see acids.

H⁺  +   Cl^-  in water is hydrochloric acid.
All the hydrogen halides in water form acidic solutions
because they all produce hydrogen ions.

hydrogen bromide + water     hydroxonium ion +  bromide ion.
HBr_(g)    +     H₂O_(l)                H₃O⁺_(aq)    +      Br^-_(aq)

For hydrogen chloride to be dissolved safely an inverted funnel is used.

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Copyright © 2008 Dr. Colin France. All Rights Reserved.