Chlorine and the Halogen Family

A set of vocabulary flashcards covering the properties, preparation, reactions, and uses of chlorine and the halogen family based on the lecture notes.

Halogens

A family of very reactive non-metals in Group 7 of the Periodic Table, each having seven valence electrons which accounts for their similar chemical properties.

Chloros

The Greek word meaning greenish-yellow, from which the name chlorine is derived.

Scheele

The scientist who discovered chlorine in $1774$ by heating concentrated hydrochloric acid with manganese(IV) oxide.

Davy

The scientist who, in $1810$, named the gas chlorine.

Manganese(IV) oxide ($MnO_2$)

A solid oxidizing agent used in the laboratory preparation of chlorine by reacting it with concentrated hydrochloric acid.

Potassium tetraoxomanganate(VII) ($KMnO_4$)

An oxidizing agent that reacts with concentrated hydrochloric acid to liberate chlorine without the need for heating.

Brine

A concentrated solution of sodium chloride used in the industrial manufacture of chlorine through electrolysis.

Liquefaction of Chlorine

The process of turning chlorine gas into a liquid, which occurs easily under a pressure of about $6$ atmospheres.

Chlorine Water

A solution formed by bubbling chlorine through water, containing a mixture of hydrochloric acid and oxochlorate(I) acid.

Oxochlorate(I) acid ($HOCl$)

An unstable acid formed during the reaction of chlorine with water that decomposes to release nascent oxygen, responsible for chlorine's bleaching action.

Bleaching Agent

The role of chlorine in the presence of water where it removes color from dyes by oxidizing them into colorless compounds.

Displacement Reaction

A reaction where chlorine removes other halogens like bromine or iodine from their salt solutions because it is more reactive.

Substitution Reaction

A controlled reaction where chlorine reacts with saturated hydrocarbons to produce chlorinated hydrocarbons and hydrogen chloride gas.

Bleaching Powder

A substance produced by bubbling chlorine gas through a freshly prepared solution of slaked lime ($Ca(OH)_2$).

Sodium trioxochlorate(V) ($NaClO_3$)

A compound formed when chlorine is bubbled through a hot concentrated solution of sodium hydroxide, commonly used as a weed-killer.

Starch-iodide paper

A test paper that turns dark blue in the presence of chlorine because chlorine displaces iodine, which then reacts with the starch.

Germicide

A property of chlorine due to its oxidizing nature, leading to its use in sterilizing water for domestic and industrial use.

Poly(chloroethene) (PVC)

A widely used plastic and synthetic rubber manufactured using chlorine.

Trichloromethane ($CHCl_3$)

An important organic solvent manufactured using chlorine.

Iron(III) chloride ($FeCl_3$)

The higher chloride formed when chlorine reacts directly with iron due to the oxidizing nature of the gas.