Ammonium Bicarbonate: Formula, Structure, Properties & Uses

Ans. The chemical and physical properties of ammonium bicarbonate are as follows:

Chemical properties: Ammonium bicarbonate is a thermally unstable colourless crystal-like solid which gets precipitated out as a by-product of the reaction between carbon dioxide and ammonia gas. At temperatures greater than 41.9 degrees celsius it readily disintegrates into carbon dioxide, ammonia and water vapour. So the entire reaction involving the production of ammonium bicarbonate is maintained at a very low temperature. It has a pH of 7.8 determining its basic nature. Ammonium bicarbonate is insoluble in most common organic solvents like benzene, ethanol, alcohol, ketone, acetone etc. On the contrary it is readily soluble in water.

Physical properties: Ammonium bicarbonate is a white/colourless solid. It is crystalline in solid structure arrangement. Ammonium bicarbonate has an ammoniacal smell. Its density is 1.586 gram/cm³. It is stable at room temperature but at temperatures above 35 ⁰ celsius it decomposes into CO₂, ammonia and water vapour.

Ans. There are several options depending on how accurate your result has to be. If we know the initial pH and you’re using pure water we can obtain a good estimate by measuring the change in pH in combination with the modelling of our system. Alternatively, we can sample our solution, add a base to the sample and then titrate between both pH values of H₂CO₃. Other options are to add Ba and also make your samples alkaline. Then you can weigh the BaCO₃ after drying.

1. Ammonium bicarbonate with acids
2. Ammonium bicarbonate with metal halides
3. Ammonium bicarbonate with sulfates?  (3 marks)

Ans. The reaction are as follows:

1. Reaction with acids: On reaction with acids like HCl , salts of ammonium are formed with chemical equation as follows :

NH₄HCO₃ + HCl → NH₄Cl + CO₂ + H₂O

2. Reaction with sulfates: On reaction with sulphates of alkaline earth elements, carbonates of such metals are formed as precipitates.

CaSO₄ + 2NH₄HCO₃ → CaCO₃ + (NH₄)₂SO₄ + CO₂ + H₂O 

3. Reaction with metal halides: Ammonium bicarbonate reacts with metal halides of alkalies to produce bicarbonates and ammonium halides.

NH₄HCO₃ + NaCl → NH₄Cl + NaHCO₃

NH₄HCO₃ + KI → NH₄I + KHCO₃

NH₄HCO₃ + NaBr → NH₄Br + NaHCO₃

Ans. Ammonium bicarbonate is prepared by combining compressed carbon dioxide and concentrated ammonia. Ammonium bicarbonate is thermally unstable at mildly higher temperatures. This is the reason why the entire reaction is carried out at a very low temperature till precipitation of NH₄HCO₃.

The same technique was used back in 1997 to produce ammonium bicarbonate in very large quantities. 

CO₂ + NH₃ + H₂O → NH₄HCO₃

Firstly the ammonia gas is made to go through a strong solution of aqueous sodium double carbonate or sesquicarbonate. The sesquicarbonate is a combination of 2 parts of NH₄HCO₃, 1 part (NH₄)₂CO₃ and 1 part H₂O. The ammonia gas gets converted to Ammonium carbonate. If the solution is prepared at 300 Celsius, crystalline ammonium carbonate can be precipitated out. When exposed to air it degrades into ammonia and ammonium bicarbonate.

Ans. Ammonium bicarbonate is also known as salt of hartshorn. In the earlier days large commercial quantities of ammonium bicarbonate by the process of dry distillation of organic matter containing nitrogen. This was not a pure form of ammonium bicarbonate rather it is one such composition among many industrially available which has ammonium bicarbonate as a constituent. It contains ammonium carbamate, ammonium carbonate. It has a strong ammonia-like smell. The sesquicarbonate or the ammonium carbamate on dissolution of alcohol gives ammonium bicarbonate.

Ans. As a safety measure the plant where its production is done , should have proper air ventilation. In case enclosures or local ventilations are not provided, respirators should be used. People working in such enclosures must use protective clothing which must be changed after work. The wastes containing ammonium bicarbonate must be deposed in a chemical landfill after proper sewage treatment to remove their toxicity. 

Other safety measures include:

• Use protective gear while working with ammonium bicarbonate and its compositions.
• Enclosures and local air ventilation systems must be effectively employed to remove the dangerous ammonia gas and filter the air.
• Direct contact or inhalation of ammonium bicarbonate must be avoided.
• Chemical waste containing ammonium bicarbonate must be duly treated at a sewage treatment plant before disposing off at a chemical landfill.

Ans. Five applications of ammonium bicarbonate are as follows :

1. Ammonium bicarbonate has extensive uses in the food processing industry. It is widely used as a leavening agent for bakery items like cookies and crackers. Before the invention of baking powder, ammonium bicarbonate was widely used in homes. The substitutes of ammonium bicarbonate can be yeast or baking powder. 
2. Ammonium bicarbonate is widely used as a reagent in research labs and industrial procedures. Ammonium bicarbonate is used in the analysis of proteins using mass spectrometry. It is also helpful in producing ammonium salts.
3. In many places ammonium bicarbonate is used as a nitrogenous fertilizer due to its ability to provide the crop with the required amounts of carbon dioxide and ammonia for its growth. Moreover, it can be applied to a variety of different soils. However, nowadays it is being replaced by urea due to its unstable nature.
4. Ammonium Bicarbonate is used as a raw material in the production of fire extinguishers. It is used for the production of paints and pharmaceutical products on a large scale.
5. It is used in the production of dyes and pigments owing to its crystalline nature. It has applications in fabric degreasing. Ammonium bicarbonate has major applications in the plastic and rubber industry. It is used as a raw material for foamed plastics.

Ans. In many places, ammonium bicarbonate is used as a nitrogenous fertilizer due to its ability to provide the crop with the required amounts of carbon dioxide and ammonia for its growth.

• Moreover, it can be applied to a variety of different soils.
• However, nowadays it is being replaced by urea due to its unstable nature.
• Ammonium bicarbonate is a natural source of ammonia so it is used as a basic fertilizer in different types of soils due to its capacity to provide the soil and crops with the required amounts of nitrogen, ammonia and carbon dioxide for proper growth.
• However, nowadays it is being replaced by urea due to productivity issues and urea being more stable is more preferred.

Ans. It is a known leavening agent and the forerunner of today’s baking powder and baking soda. Originally made up of the bottom antlers of reindeer, this is often considered as the predecessor of the new baking soda. North Europeans make it useful for the gingerbread cookies, light and crisp. One of the disadvantages is that it can impart an unpleasant ammonia flavour, so it is best utilised for cookies and pastries that are sufficiently small to permit the ammonia odour to dissipate while baking. It is easily available in drug stores, bakery supply stores, etc. Must be grounded into a powder before using it. 

Ans. Ammonium bicarbonate is widely used as a reagent in research labs and industrial procedures. Ammonium bicarbonate is used in the analysis of proteins using mass spectrometry. It is also helpful in producing ammonium salts.

• Ammonium bicarbonate is prepared by combining compressed carbon dioxide and concentrated ammonia. 
• Itis thermally unstable at mildly higher temperatures.
• This is the reason why the entire reaction is carried out at a very low temperature till precipitation of NH₄HCO₃.

Ans. Ammonium bicarbonate can be a useful leavening agent in biscuits, especially for recipes that lack acidic ingredients or require a gentler initial rise. However, it's crucial to balance the amount used to avoid an ammonia aftertaste and consider the potential impact of moisture content in the biscuit dough. Bakers might choose alternative leavening agents or combinations depending on the desired texture and flavour profile of their biscuits.