Formulae [1]
Give the formula of liquid ammonia.
NH3
Key Points
key Points: Ammonia
- Molecular Details: Ammonia (NH₃) has a molecular mass of 17 and exhibits covalent bonding with a lone pair on nitrogen.
- Occurrence: Found in small amounts in air and water; occurs in compounds like ammonium chloride and ammonium sulphate.
- Formation: Produced by bacterial decomposition of urea in decaying organic matter and urine.
- Forms of Use: Used as dry gas, liquid (under pressure), and as liquor ammonia fortis—a saturated aqueous solution with density 0.880.
- Laboratory Use: Dilute ammonia solution is widely used as a reagent in laboratories.
Key Points: Manufacture of Ammonia
- Reactants: Nitrogen and hydrogen in 1:3 ratio by volume.
- Conditions: 450–500°C, 200+ atm pressure, iron catalyst with molybdenum or Al₂O₃.
- Reaction: Reversible, exothermic, and reduces volume:
N₂ + 3H₂ ⇌ 2NH₃ + heat - Yield: 15% per pass; up to 98% yield by recycling unreacted gases.
- Purification: CO₂, CO, and H₂S must be removed to protect the catalyst.
Key Points; Physical Properties of Ammonia
| Property | Description |
|---|---|
| Colour | Colourless gas |
| Smell | Strong, pungent odour |
| Taste | Slightly bitter (alkaline) |
| Effect | Non-poisonous but irritates eyes and lungs; dangerous in large amounts |
| Density | Vapour density = 8.5 (lighter than air) |
| Nature | Alkaline |
| Liquefaction | Liquefies at 10°C under 6 atm pressure |
| Boiling Point | –33.5°C |
| Freezing Point | –77.7°C |
| Solubility | Highly soluble; 1 vol. water dissolves 702 vols |
Key Points: Chemical Properties of Ammonia
- Decomposition: Ammonia breaks into nitrogen and hydrogen on heating.
- Basic Nature: Aqueous ammonia is a weak base and turns red litmus blue.
- Burning: Does not burn in air, but burns in oxygen forming nitrogen and water.
- Reducing Agent: Reduces hot metal oxides and chlorine.
- Reactions: Forms ammonium salts with acids and hydroxide precipitates with metal salts.
Key Points: Uses of Ammonia
- Refrigerant: Liquid ammonia is a good, eco-friendly refrigerant—better than harmful CFCs.
- Cleaning & Lab Use: Used for cleaning stains and as a lab reagent to detect metal ions.
- Fertilizers & Explosives: Used to make urea, ammonium nitrate, and other useful ammonium salts.
Important Questions [36]
- Identify the Cations in the Following Case : Nh4oh Solution, When Added to the Solution (B), Gives White Ppt Which Does Not Dissolve in Excess.
- Ammonia gas is collected by ______.
- Distinguish between the given pair of compounds using the test given within brackets: Iron (II) sulphate and iron (III) sulphate (using ammonium hydroxide)
- Name the Other Ion Formed When Ammonia Dissolves in Water
- Identify the Cations in the Following Case: Naoh Solution, When Added to Solution (C), Gives White Ppt Which is Insoluble in Excess
- State the terms/process for the following: The name of the process by which Ammonia is manufactured on a large scale.
- Name the gas evolved when the following mixtures are heated. Calcium hydroxide and ammonium chloride.
- State a relevant reason for the following: Ammonia gas is not collected over water.
- State One Relevant Observation for the Following When Ammonia Gas is Burnt in an Atmosphere of Excess Oxygen.
- The acid which is prepared by catalytic oxidation of ammonia.
- State the conditions required for the given reaction to take place: Catalytic oxidation of ammonia to nitric oxide.
- Ammonia Gas is Passed Over Heated Copper (I) Oxide.
- Identify the substance underlined: The catalyst used to oxidise ammonia.
- Identify the substance underlined: The organic compound which when solidified, forms an ice like mass.
- Name the Gas Evolved in Each of the Following Cases : Alumina Undergoes Electrolytic Reduction.
- Ethene Undergoes Hydrogenation Reaction.
- Name the Gas Evolved in Each of the Following Cases : Ammonia Reacts with Heated Copper Oxide.
- Study the flow chart given and give balanced equations to represent the reactions A, B and C: Mg3N2 ->[A] NH3 <=>[B][C] NH4Cl
- Copy and Complete the Following Table Which Refers to the Industrial Method for the Preparation of Ammonia and Sulphuric Acid:
- Give a balanced chemical equation for the following: Lab. preparation of ammonia using an ammonium salt.
- Give Balanced Chemical Equations for of the Following : Reaction of Ammonia with Excess Chlorine
- Give a balanced chemical equation for the following: Reaction of ammonia with sulphuric acid.
- The metallic hydroxide which forms a deep inky blue solution with excess ammonium hydroxide solution is ______.
- Ammonia burns in oxygen, as shown below. 4NHA3+3OA2⟶2NA2+6HA2O If 240 cc of ammonia is burnt in 300 cc of oxygen, find out the composition of the resultant gaseous mixture at room temperature.
- State One Relevant Observation for Given Reactions: Burning of Ammonia in Air.
- Give a Balanced Chemical Equation for Catalytic Oxidation of Ammonia
- Give a Balanced Chemical Equation For Reaction of Ammonia with Nitric Acid
- The Equation 4nh3 + 5o2 → 4no + 6 H2o, Represents the Catalytic Oxidation of Ammonia. If 100 Cm3 of Ammonia is Used Calculate the Volume of Oxygen Required to Oxidise the Ammonia Completely
- Write Balanced Chemical Equations for the Following: When the Excess of Ammonia is Treated with Chlorine.
- Write Balanced Chemical Equations for the Following: an Equation to Illustrate the Reducing Nature of Ammonia.
- Select from the List the Gas that Matches the Description Given in Case this Gas is Used as a Reducing Agent in Reducing Copper Oxide to Copper
- Write a Balanced Chemical Equation for the Following: Reaction of Ammonia with Heated Copper Oxide.
- State one relevant observation for the following: Burning of ammonia in excess of oxygen.
- A compound which undergoes thermal dissociation.
- On passing ammonia gas over heated copper oxide for some time, a reddish-brown residue is left behind. What property of ammonia is demonstrated here?
- Ammonia reacts with excess chlorine to form ______.
Concepts [9]
- Concept of Ammonia
- Preparation of Ammonia Gas
- Recognition and Identification of Gases
- Preparation of Aqueous Ammonia
- Manufacture of Ammonia (Haber's Process)
- Physical Properties of Ammonia
- Chemical Properties of Ammonia
- Tests for Ammonia Gas and Ammonium Ion
- Uses of Ammonia
