78% of atmosphere is covered by nitrogen gas. Gaseous nitrogen is not a reactive compound in room conditions. Nitrogen contains in lot of compounds such as ammonia, different oxides of nitrogen (NO, NO2), nitric acid and more. Nitrogen gas is used in domestic and chemical industrial purposes.
In this lesson, we learn followings of nitrogen gas.
There are several ways to produce nitrogen gas in laboratory scale and industrial scale. All reactions of nitrogen preparing in the laboratory is explained below.
Liquid nitrogen is used as a coolant. Liquid nitrogen only exist between -2100C - -1960C. So you can see temperature of liquid nitrogen is very low.
Gaseous nitrogen is used as a filling agent in food industry because its reactivity characteristics are poor. There are more uses of nitrogen gases and they are explained in detail below.
Ammonia is oxidized to nitrogen gas.
Send ammonia gas to the hot copper oxide. Ammonia will oxidized to nitrogen gas and copper oxide is reduced to copper metal. Furthermore water vapor is given as other product. Copper oxide is black colour and produced copper is red colour.
Nitrogen and water vapor are given as products. Nitrogen atoms are at two different oxidation states at Ammonium cation and nitrite anion.
Heat orange colour potassium dichrmoate ( K2Cr2O7). Nitrogen gas, chromium oxide ( Cr2O3 ), and water are given. Chromium oxide is green colour.
When sodium azide has enough heat, it decomposes to sodium and nitrogen gas. This reaction is used in air bags in vehicles and detonator.
This is another reaction to prepare nitrogen gas. When heat is available, silver oxide decomposes to silver metal and oxygen gas. Then produced oxygen gas will reacts with ammonia to give nitrogen gas.
Copper oxide (CuO) is stable to heat. It does not decompose to metal and oxygen gas when heat. Therefore, ammonia does not react with zinc oxide.
A redox reaction reaction occurs. Active part of bleaching powder is hypochlorite anion (OCl-). Nitrogen gas, calcium hypochlorite and water are products.
Nitric oxide is reduced to nitrogen and ammonia is oxidized. As products nitrogen gas and water vapor are given.
No. Zinc oxide does not give oxygen gas when heating (Zinc oxide does not decompose). So due to no oxygen gas, ammonia does not react and nitrogen gas is not given.
Air is cooled and pressurized to liquidize. Then liquid air distillate to separate nitrogen.
Send produced gas to a magnesium metal piece and give some heat to occur the reaction (when temperature is high, it increses the reaction rate). We know alkali earth metals react with both oxygen and nitrogen gases and give metal nitrides and metal oxides.
After some time, reacted metal piece is added to the water. Both magnesium oxide and magnesium nitride will give two precipitates.
N2 is a very inactive element. A very strong triple bond (946 kJmol-) is the reason for this inactivity of N2.
Why nitrogen gas is used in packaing goods?
Nitrogen gas is not reactive and at ordinary conditions and does not react with goods inside packages.
When both compounds are mixed, it gives ammonium cations and nitrite anions. When ammonium cations and nitrite anions are together and get heat, nitrogen gas emits.
Do not mix sodium nitrate. It will give nitrous oxide (N2O) instead of nitrogen gas.
When ammonia is heated with oxygen in thee presence of copper, nitric oxide (NO) is given. Copper is behaved as a catalyst in this reaction.
Heat + Cu (as a catalyst) + 4NH3 + 5O2 = 4NO + 6H2O
But, when ammonia gas is heated with CuO, ammonia is reduced to nitrogen gas.
2NH3 + 3CuO = N2 + 3Cu + 3H2O
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