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Why does chlorine react with many hydrogen-containing compounds?

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A labeled diagram of the chlorine element from the periodic table shows its atomic number 17, symbol Cl, electron configuration, and atomic weight range. The box is shaded green to indicate chlorine is a halogen, with icons for orthorhombic crystal structure, gas state at room temperature, and strong acidity. A key explains the icons and colors used. — chlorine Properties of chlorine.

Chlorine reacts with many hydrogen-containing compounds primarily because of its high electronegativity and high electron affinity, which result in an exceptionally strong affinity for hydrogen.1

This chemical attraction is so significant that chlorine can readily displace or substitute hydrogen atoms in various substances. For example, when reacting with hydrocarbons, chlorine atoms are substituted for hydrogen atoms in a successive manner. If the hydrocarbon is unsaturated, chlorine atoms can also readily add to the double or triple bonds present in the molecule.1