1. Chlorine and its compounds
By OSHIN Oluwatomisin
Chlorine and its compounds     

2. (As an oxidizing agent, as a bleaching, And Reaction with alkalis)
OBJECTIVES
Physical properties of chlorine
Chemical property of Chlorine
(As an oxidizing agent, as a bleaching, And Reaction with alkalis)
Test for Chlorine
Uses of Chlorine

3. Physical Properties of chlorine

4. chlorine as an element
Chlorine is a chemical element with symbol Cl and atomic number 17. Chlorine is in the halogen group (7) and is the second lightest halogen following fluorine. The element is a yellow-green gas under standard conditions, where it forms diatomic molecules(Cl2). Chlorine has the highest electron affinity and the fourth highest electronegativity of all the reactive elements. For this reason, chlorine is a strong oxidizing agent. Free chlorine is rare on Earth, as it is very reactive trying to achieve a stable electron octet state either by;
* gaining an electron from a metal of group 1 and 2 in an electrovalent compound(NaCl, CaCl2) to form a negative ion(Cl-) or
* sharing a pair of electrons in a single covalent bond with another atom of chlorine(Cl-Cl=Cl2) or with hydrogen(H-Cl=HCl)

5. As an oxidizing agent
Chlorine is a powerful oxidizing agent because of its ability to remove hydrogen and its readiness to accept electrons from reducing agents to form chloride ions. . Chlorine has the highest electron affinity and the fourth highest electronegativity of all the reactive elements. For this reason, chlorine is a strong oxidizing agent.
typical examples of the oxidizing behavior of chlorine are as follows
With iron(II) salts: Chlorine oxidizes a solution of green iron(II) chloride to yellow iron(III) chloride.
2FeCl2(aq) + Cl2(g)  2FeCl3(aq)
Ionic ally,
2Fe2+(aq) + Cl2(g) Fe3+(aq) + 2Cl-(aq)
With trioxosulphate(IV) ion: When bubbled through a freshly prepared solution of trioxosulphate(IV) acid, chlorine oxidizes the trioxosulphate(IV) ion to tetraoxosulphate(VI)
H2SO3(aq) + H2O(l) + Cl2(g)  H2SO4(aq) + 2HCl(aq)
Ionically,
SO32-(aq) + 2O(l) + Cl2(g) SO42-(aq) + 2H+(aq) + 2Cl-(aq)

6. HOCl(aq)  HCl(aq) + [O]
As a bleaching agent
Chlorine is used in pools and drinking water because it is a great disinfectant. It is able to kill bacteria and algae, among other things. Chlorine also makes a great stain remover, but not because of the chlorine itself. Natural stains (as well as dyes) produced by everything from mildew to grass come from chemical compounds called chromophores. Chromophores can absorb light at specific wavelengths and therefore cause colors. When chlorine reacts with water, it produces hydrochloric acid and atomic oxygen. The oxygen reacts easily with the chromophores to eliminate the portion of its structure that causes the color.
Chlorine is a common bleaching agent. In the presence of water, it bleaches most dyes and inks, except those containing carbon, eg printers ink. the bleaching action of chlorine is due to its ability to react with water to form oxochlorate(I) acid .the latter is unstable and decomposes to release oxygen which oxidizes the dye to form a colourless compound
HOCl(aq)  HCl(aq) + [O]
Dye + [O]  (Dye + O)
Colored Colorless

7. Its reaction with alkali metals
1.All alkali metals react with chlorine gas to form white metal chlorides salt.
Group 1 Metals + Chlorine Gas → Metal Chloride
2.The metal chlorides salt formed is soluble in water to give a neutral solution of pH 7.
3.The reactivity increases down the group from lithium, sodium to potassium.
Lithium + Chlorine
2Li + Cl2 → 2LiCl
Observation Lithium burned slowly with a reddish flame . A white solid is produced.
Sodium + Chlorine
2Na + Cl2 → 2NaCl
Observation Sodium burned brightly with a yellowish flame. A white solid is produced..

8. Reaction with alkalis

9. Test for chlorine
The above video shows the damp litmus paper test which involves placing litmus paper in the jar containing unknown gas. As a result the litmus becomes bleached indicating the presence of chlorine
Another method includes the starch-iodide test; This involves dipping a piece of damp starch-iodide into the unknown gas. If the paper turns dark blue ,then the gas is chlorine. Chlorine displaces iodine from the starch-iodide and the liberated iodine turns the starch blue.
2KI(aq) + Cl(g) KCl(aq) + I2(s)

10. Uses of chlorine
Chlorine is a powerful germicide because of its oxidizing nature. It is used in the sterilization of water for domestic and industrial use and in the treatment of sewage
Used as a bleaching agent for cotton linen and wood-pulp .Its too strong for bleaching animal fibres like silk and wool
Used in the production of:
-Important solvents such as trichloromethane, tetrachloromethane etc
-The widely used plastic ,poly(chloroethane) and synthetic rubber
-Hydrochloric acid
-Potassium trioxochlorate(V) which is used in making matches and fireworks
-Bleaching agents such as bleaching powder
-Domestic antiseptics