Which compounds are used in laboratory prepration of oxygen gas?

Answer 1

Lab preparation of oxygen

To prepare oxygen; you would need the following apparatus:

1.Test tubes

2.Manganese (IV) dioxide (MnO2)

3. Hydrogen peroxide (it must be fresh and kept away from light)(H2O2)

4. Wooden splinter (only needed if you are going to check how oxygen helps in combustion).

5.Candle and matchsticks.

Method:

1.First, take the test tube and put a little bit of MnO2 (Manganese dioxide)

2. At this time, you will need a friend's or someone else's help (only if you are requiring it to check how oxygen helps in combustion). First, tell your friend to light the candle and to ignite the splinter using the candle. At that time, take a small amount of hydrogen peroxide in a beaker or test tube. Then, tell him/her to to bring the wooden splinter close to the test tube. As soon as he/she brings it, put a little bit of hydrogen peroxide (not more than 1ml). You should see the reaction forming a gas, which looks like smoke. This gas is Oxygen.

3. What happens to the splinter when you bring it close to Oxygen? Of course!

The splinter burns more brightly and intensely.

4. Should you want to only collect Oxygen, you need not do the second part of the second step.

Precautions:

1. Do not drop the test tubes.

2. Always wear gloves while performing chemical experiments.

3. Always wear lab coats while doing the same.

4. Do NOT eat or manganese oxide or rub them on your eyes. Serious problems may occur, which even might result in blindness or death.

5. Do NOT put warmed hydrogen peroxide on your skin. You might get a boil.

6. Never stand too close to the test tube.

7. If you are untrained, always seek for someone who is better at you in performing lab experiments, or anyone who already has done the lab preparation of Oxygen.

8. Keep H2O2 and MnO2 away from children.

9. If Oxygen gets into your eyes and you get an irritation, wash your eyes with cold water immediately.

I am sure this helped! Good luck in becoming a RAD scientist!

Answer 2

Because oxygen is a component of air, it has been studies extensively over the centuries and there is a large number of different methods for its preparation. The most convenient method for preparing oxygen in the laboratory involves either the catalytic decomposition of solid potassium chlorate or the catalytic decomposition of hydrogen peroxide. Potassium chlorate decomposes at a low temperature if previously mixed with manganese dioxide which is a catalyst for the decomposition. Only the potassium chlorate is decomposed, and no perchlorate is formed : 2 KClO3 ==> 2 KCl + 3 O2 The decomposition of hydrogen peroxide using manganese dioxide as a catalyst also results in the production of oxygen gas. 2 H2O2 ==> 2 H2O + O2 The electrolysis of acidified water is carried out in a Hofmann Voltameter. Oxygen is evolved at the positive electrode in the electrolysis. 2 H2O ==> 2 H2 + O2 A solution of barium hydroxide with nickel electrodes may also be used. However, on prolonged electrolysis an explosive mixture of oxygen and hydrogen may be evolved at the positive electrode. Oxygen is obtained from water by passing a mixture of steam and chlorine through a strongly heated silica tube containing pieces of broken porcelain. 2 H2O + 2 Cl2 ==> 4 HCl + O2 The hydrogen chloride is removed by a wash-bottle containing sodium hydroxide solution and the Oxygen collected over water. Oxygen may be obtained by heating some metallic oxides. * When mercuric oxide is strongly heated in a hard glass tube, it decomposes, globules of Mercury collect in the cooler part of the tube and oxygen gas is evolved. It may be collected over mercury in a pure and dry state. · · 2 HgO ==> 2 Hg + O2 * Silver oxide decomposes at a lower temperature than mercuric oxide. When the silver oxide is prepared by precipitation from a solution of silver nitrate by a solution of pure potassium hydroxide in absence of atmospheric carbon dioxide the silver oxide formed gives very pure oxygen. · · 2 Ag2O ==> 4 Ag + O2 * Many higher oxides of metals decompose on heating forming the lower oxides and oxygen gas. * ** 2 BaO2 ==> 2 BaO + O2 ** 3 MnO2 ==> Mn3O4 + O2 ** 2 PbO4 ==> 6 PbO + O2 ** 2 PbO2 ==> 2 PbO + O2 * Manganese dioxide evolves oxygen more readily when heated with concentrated sulphuric acid. · · 2 MnO2 + 2 H2SO4 ==> 2 MnSO4 + 2 H2O + O2 Some salts containing oxygen decompose and release oxygen gas on heating. * Potassium nitrate melts on heating and at a slightly high temperature decomposes, giving off bubbles of oxygen and forming potassium nitrite which solidifies on cooling. · · 2 KNO3 ==> 2 KNO2 + O2 * Potassium chlorate crystals melt when heated in a hard glass tube at 360 degC and then decompose to form potassium chloride and releasing oxygen. · · 2 KClO3 ==> 2 KCl + 3 O2 * Potassium permanganate which is a purple crystalline solid, decomposed without fusing on heating to 240 degC, forming a black powder consisting of a mixture of potassium manganate and manganese dioxide and releasing oxygen. · · 2 KMnO4 ==> K2MnO4 + MnO2 + O2 * Potassium permanganate explodes violently when heated with concentrated sulphuric acid. However, when a solution of hydrogen peroxide is mixed with a solution of the permanganate and diluted sulphuric acid added, the two compounds decompose together, forming a nearly colourless solution, and oxygen is evolved. · · 2 KMnO4 + 3 H2SO4 + 5 H2O2 ==> K2SO4 + 2MnSO4 + 8H2O +5O2 * Chromic trioxide which is a red crystalline solid, melts on heating at about 420 degC, leaving a green residue of chromic oxide and evolves oxygen. · · 4 CrO3 ==> 2 Cr2O3 + 3 O2 * Potassium dichromate which is a bright-red crystalline solid, melts on heating and when strongly heated releases oxygen leaving a mixture of yellow potassium chromate which is soluble in water, and green chromic oxide, which is insoluble in water. · · 4 K2Cr2O7 ==> 4 K2CrO4 + 2 Cr2O3 + 3 O2 * Chromium trioxide and potassium dichromate when heated with concentrated sulphuric acid forms chromic sulphate and releases oxygen. · · 4 CrO3 + 6 H2SO4 ==> 2 Cr2(SO4)3 + 6 H2O +3 O2 · · 2 K2Cr2O7 + 10H2SO4 ==> 4 KHSO4 + 2 Cr2(SO4)3 + 8 H2O +3 O2 Oxygen may be obtained from the atmosphere in a chemical process, by heating mercury in a confined volume of air, when the oxygen reacts with the mercury to form mercuric oxide. The mercuric oxide so formed is then heated strongly, when it decomposes and pure oxygen is evolved. In a similar process, if yellow lead monoxide is carefully heated in an iron dish and freely exposed to air, it takes up oxygen from the air and forms red lead. 6 PbO + O2 ==> 2 Pb3O4 Yellow Red Lead LeadMonoxide On heating strongly, the red lead decomposes into lead monoxide and Oxygen gas which is evolved. 2 Pb3O4 ==> 6 PbO + O2

Answer 3

There are a number of procedures to produce oxygen. But in laboratory, the process of electrolysis of water is commonly used. In this method, oxygen is produced at anode and hydrogen is produced at cathode.

Equations:-

Cathode reaction (reduction): 2H2O(l)+ 2e- -> H2(g)+ 2OH-(aq)

Anode reaction (oxidation): 4OH-(aq) -> O2(g)+ 2H2O(l)+ 4e-

Combined reaction: 2H2O(l) -> 2H2(g)+ O2(g)

Answer 4

Oxygen