NEB Class 11 Chemistry Important Question Collection for Final Exam

Table of Contents

Physical Chemistry

1. What is an ideal gas? Under what conditions will a gas nearly behave like an ideal gas?
   Answer: An ideal gas is a hypothetical gas whose behavior is perfectly described by the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin. A gas behaves like an ideal gas at low pressures, high temperatures, and when the gas molecules are non-polar and far apart.
2. Why is Hund’s rule called the rule of maximum multiplicity?
   Answer: Hund's rule is called the rule of maximum multiplicity because it ensures that electrons occupy empty orbitals singly before pairing up, resulting in parallel spins and maximizing the total spin, or multiplicity, which leads to lower energy.
3. Define the terms:
   a) Surface Tension
   b) Viscosity
   c) Aqueous Tension
   Answer:
   a) Surface Tension: Surface tension is the force acting on the surface of a liquid that causes it to minimize its surface area, behaving as if it were a stretched elastic membrane.
   b) Viscosity: Viscosity is the measure of a fluid's resistance to gradual deformation by shear stress or tensile stress.
   c) Aqueous Tension: Aqueous tension is a measure of the partial pressure of water vapor in the atmosphere above a surface of pure water.
4. Give proper reason for the following:
   1. Rain (liquid) drops are spherical.

   Answer: Raindrops are spherical due to surface tension. Surface tension minimizes the surface area of the liquid, causing it to form a spherical shape, which has the minimum surface area for a given volume.

   2. Alcohol can flow easily but honey cannot.

   Answer: Alcohol has lower viscosity (resistance to flow) compared to honey. Viscosity is a measure of a liquid's resistance to flow. Honey has a higher viscosity due to its higher molecular weight and more complex structure, making it flow less easily than alcohol.

   3. Evaporation takes place from the surface of liquid.

   Answer: Evaporation occurs from the surface of a liquid because the molecules at the surface have higher energy and can escape into the air as vapor. This process continues until equilibrium is reached.

   4. It is more efficient to wash clothes in hot water than cold water.

   Answer: Washing clothes in hot water is more efficient because hot water has higher kinetic energy, which helps to break down and dissolve dirt and stains more effectively than cold water.

5. What is evaporation? How does it differ from boiling?

   Answer: Evaporation is the process by which molecules in a liquid state (e.g., water) gain enough energy to enter the gaseous state (e.g., water vapor). It differs from boiling in that evaporation occurs at the surface of a liquid at temperatures below its boiling point, while boiling occurs throughout the liquid at its boiling point.

6. Distinguish between:
   1. Isotropic and anisotropic substances giving an example of each.

   Aspect	Isotropic	Anisotropic
   Definition	Have uniform physical properties in all directions.	Have different physical properties in different directions.
   Example	Glass (uniform transparency)	Wood (different strength in different directions)
   1. Optical Properties	Same in all directions	Different in different directions
   2. Mechanical Properties	Uniform in all directions	Varies with direction
   3. Electrical Conductivity	Same in all directions	Differs with direction
   4. Thermal Conductivity	Equal in all directions	Varies with direction
   5. Structural Properties	Has a homogeneous structure	Has an anisotropic structure

   2. Crystalline and amorphous solid.

   Aspect	Crystalline Solid	Amorphous Solid
   Definition	Have a regular and repeating atomic arrangement.	Lack a regular atomic arrangement.
   Example	Salt (regular repeating pattern)	Glass (random arrangement)
   1. Atomic Arrangement	Highly ordered	Random
   2. Melting Point	Have a sharp melting point	Softens over a range of temperatures
   3. Cleavage	Exhibit cleavage	Do not exhibit cleavage
   4. Transparency	Can be transparent	May or may not be transparent
   5. Crystalline Nature	Crystalline solids have a definite geometric shape	Amorphous solids do not have a definite geometric shape

   3. Crystal lattice and unit cell.

   Aspect	Crystal Lattice	Unit Cell
   Definition	3D arrangement of atoms in a crystal	Smallest repeating unit of the lattice
   Example	Diamond (repeating pattern of carbon atoms)	Cubic (simplest repeating unit in a cubic lattice)
   1. Size	Extends throughout the crystal	Smaller than the crystal lattice
   2. Definition	It is the whole 3D arrangement of the atoms in a crystal	It is a part of the crystal lattice that repeats in all directions
   3. Nature	It is imaginary and extends to infinity	It is real and occupies space in the crystal lattice
   4. Properties	It has the properties of the entire crystal	It has the properties of a small part of the crystal
   5. Repeating Unit	It is made up of unit cells	It is the smallest unit of the crystal lattice that repeats itself

7. Mention one important character and an example of each:
   1. Efflorescence (efflorescent substance)

   Answer: Efflorescence is the process by which a substance loses water of crystallization when exposed to air. Example: Sodium carbonate (washing soda) forms white powder on exposure to air.

   2. Deliquescence (deliquescent substance)

   Answer: Deliquescence is the process by which a substance absorbs moisture from the air and becomes liquid. Example: Calcium chloride absorbs moisture from the air and forms a liquid solution.

   3. Hygroscopy (hygroscopic substance)

   Answer: Hygroscopy is the ability of a substance to absorb and retain moisture from the air. Example: Silica gel is a hygroscopic substance used to absorb moisture in packaging.

8. Why electron does not jump into the nucleus.

   Answer: Electrons do not jump into the nucleus because they are bound to the nucleus by electrostatic forces. These forces keep the electrons in orbit around the nucleus at specific energy levels, preventing them from falling into the nucleus.

9. Define:
   1. Nuclear fusion

   Answer: Nuclear fusion is the process in which two atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy. Example: The sun produces energy through nuclear fusion of hydrogen nuclei.

   2. Nuclear fission

   Answer: Nuclear fission is the process in which a heavy atomic nucleus splits into two or more lighter nuclei, releasing a large amount of energy. Example: Nuclear power plants use nuclear fission to generate electricity.

   3. Thermonuclear reaction

   Answer: A thermonuclear reaction is a nuclear reaction that takes place at high temperatures. Example: The fusion of hydrogen into helium in stars is a thermonuclear reaction.

10. Distinguish between:
    1. Nuclear reactions and chemical reactions.
    Answer:

    Aspect	Nuclear Reactions	Chemical Reactions
    Basic Process	Involve changes in the nuclei of atoms	Involve changes in the electron configuration
    Energy Changes	Involve large energy changes (e.g., nuclear fusion)	Typically involve small energy changes
    Mass Changes	May result in significant mass changes (e.g., fission)	Mass changes are negligible
    Examples	Nuclear fission, nuclear fusion	Combustion, oxidation-reduction reactions

    2. Controlled nuclear fission and uncontrolled nuclear fission.
    Answer:

    Aspect	Controlled Nuclear Fission	Uncontrolled Nuclear Fission
    Regulation	Done in a controlled manner, often for power generation	Happens spontaneously or uncontrollably
    Chain Reaction	Typically controlled to prevent runaway reactions	Can lead to chain reactions, potentially explosive
    Examples	Nuclear reactors, controlled nuclear energy production	Atomic bombs, nuclear accidents like Chernobyl

11. What is hydrogen bond? Differentiate between intramolecular and intermolecular H- bonding with example.

12. Define dipole moment and give its two important applications.

13. Write down the Lewis structure of:
    1. (NH₄)₂SO₄
    2. H₂SO₄, etc.

14. Differentiate between polar and non-polar covalent bonds with one example of each.

    Answer:

15. State modern periodic law. On what basis does Mendeleev’s periodic law differ from modern periodic law.

    Answer:

16. What is periodicity and its causes? How do atomic radii( size) vary in a group and a period?

    Answer:

17. State and explain the law of equivalent proportion/ reciprocal proportion/ multiple proportion.

18. Define the terms:
    1. Oxidation
    2. Oxidation number(state)
    3. Reduction
    4. Oxidant/reductant
    Answer:
    1. Oxidation: The process in which a substance loses electrons, resulting in an increase in its oxidation number.
    2. Oxidation number (state): A number assigned to an element in a chemical compound that represents the number of electrons lost or gained by an atom of that element in the compound. It indicates the degree of oxidation of an atom.
    3. Reduction: The process in which a substance gains electrons, resulting in a decrease in its oxidation number.
    4. Oxidant/reductant: An oxidizing agent (oxidant) is a substance that causes oxidation by accepting electrons from another substance. A reducing agent (reductant) is a substance that causes reduction by donating electrons to another substance.

19. What is a redox reaction? Show that oxidation and reduction take place simultaneously.

    Answer:

    A redox (reduction-oxidation) reaction is a type of chemical reaction that involves a transfer of electrons between two species. In a redox reaction, one substance loses electrons (oxidation) while another gains electrons (reduction).

    To show that oxidation and reduction take place simultaneously, we can consider the example of the reaction between copper oxide (CuO) and hydrogen gas (H₂) to form copper metal (Cu) and water (H₂O):

    CuO + H₂ → Cu + H₂O

    In this reaction, copper oxide is reduced to copper (CuO → Cu), which involves the gain of electrons (reduction), while hydrogen gas is oxidized to water (H₂ → H₂O), which involves the loss of electrons (oxidation). The overall reaction demonstrates both oxidation and reduction processes occurring simultaneously.

20. Calculate the weight of 11.2 liters of CO₂ gas at STP.

21. Define equilibrium constant (Kc). Write the relation between Kp and Kc for the following reaction:
    H₂(g) + I₂(g) ⇄ 2HI(g)

22. How do an increase in temperature and pressure affect the equilibrium of the following reaction:
    N₂(g) + H₂(g) ⇄ 2NH₃(g) + Heat

Inorganic Chemistry

Non-Metal

1. What is nascent hydrogen? Mention an example to show nascent hydrogen is a more powerful reducing agent than molecular hydrogen.

2. Name the isotopes of hydrogen. Which isotope is least abundant/radioactive?

3. Differentiate between ortho and para hydrogen.

4. Mention an important use of:
   1. Deuterated water (heavy water)
   2. Tritium
   3. Ozone
   4. Nascent hydrogen
   5. Deuterium.
5. Write two examples of each:
   1. Amphoteric oxide
   2. Neutral oxide
   3. Peroxide
   4. Mixed oxide.

6. How does the formation of ozone take place in the stratosphere? What is meant by tailing of mercury?

7. Why is water an excellent solvent for polar substances?

8. Explain why:

   1. Ammonia cannot be dried by passing through conc. H₂SO₄.
   Answer:

   Concentrated sulfuric acid (H₂SO₄) reacts with ammonia (NH₃) to form ammonium sulfate ((NH₄)₂SO₄) and water, instead of drying it.

   2. Conc. HNO₃ is stored in a dark bottle?
   Answer:

   Concentrated nitric acid (HNO₃) is stored in a dark bottle to prevent the decomposition of the acid by light, which can lead to the formation of nitrogen dioxide (NO₂) and oxygen (O₂).

   3. Phosphorus is stored in water.
   Answer:

   White phosphorus (P₄) is stored in water to prevent its exposure to air, as it is highly reactive and can spontaneously ignite in air.

   4. Conc. H₂SO₄ is diluted by adding acid into water but not water into acid?
   Answer:

   Adding water to concentrated sulfuric acid can cause a violent reaction due to the heat generated. Adding acid to water allows for better control of the reaction and prevents splattering of the acid.

   5. H₂SO₄ always acts as an oxidizing agent but not a reducing agent.
   Answer:

   Concentrated sulfuric acid acts as an oxidizing agent in many reactions, such as with metals, but it is not a reducing agent because it does not readily donate electrons to other substances.

9. What is the laboratory test of:
   1. Nitrate ion (i.e., Nitric acid) (i.e., ring test)
   2. Cl^–, Br^–, and I^–
   3. Sulphate ion (Sulphuric acid)

10. What is aqua regia? Write its reaction with gold.

    Answer:

    Aqua regia is a mixture of concentrated nitric acid (HNO₃) and concentrated hydrochloric acid (HCl) in a ratio of 1:3. It is used to dissolve noble metals such as gold and platinum.

    Reaction with gold:

    Au + 3HNO₃ + 4HCl → HAuCl₄ + 3NO₂ + 2H₂O

11. Compare the bleaching properties of Cl₂ and SO₂

    Answer:

    Both chlorine (Cl₂) and sulfur dioxide (SO₂) are bleaching agents, but they act differently. Cl₂ is a more powerful bleaching agent and is used in the bleaching of paper, textiles, and wood pulp. SO₂ is a milder bleaching agent and is mainly used in the food industry for bleaching dried fruits and vegetables.

12. Give a chemical reaction for the preparation of HCl. Why HBr and HI cannot be prepared by treating conc. H₂SO₄ with bromide and iodide?

    Answer:

    Preparation of HCl:

    NaCl + H₂SO₄ → NaHSO₄ + HCl

    HBr and HI cannot be prepared by treating conc. H₂SO₄ with bromide and iodide because bromide and iodide ions are stronger reducing agents compared to chloride ions. Therefore, they are oxidized by concentrated sulfuric acid to form bromine (Br₂) and iodine (I₂), respectively, instead of the desired hydrogen bromide (HBr) and hydrogen iodide (HI).

13. How does bromine/chlorine react with hot and conc. NaOH?

    Answer:

    Bromine or chlorine reacts with hot and concentrated sodium hydroxide (NaOH) to form sodium bromide (NaBr) or sodium chloride (NaCl), respectively, along with water and liberating oxygen gas.

14. Why is CO extremely poisonous?

    Answer:

    Carbon monoxide (CO) is extremely poisonous because it binds more strongly to hemoglobin in red blood cells than oxygen does, leading to the formation of carboxyhemoglobin. This reduces the blood's ability to carry oxygen, leading to hypoxia and potentially death.

15. What is meant by allotropy? Which one is the hardest allotrope and the latest discovered allotrope of carbon? Write one use of each.

    Answer:

    Allotropy is the phenomenon in which an element exists in two or more different forms (allotropes) in the same physical state. The hardest allotrope of carbon is diamond, while the latest discovered allotrope is graphene. One use of diamond is in cutting, grinding, and drilling due to its extreme hardness. Graphene has potential applications in electronics, materials science, and medicine due to its unique properties.

16. What happens when white phosphorus is heated with aqueous caustic soda? (i.e., preparation of phosphine).

    Answer:

    When white phosphorus is heated with aqueous caustic soda (sodium hydroxide), phosphine gas (PH₃) is formed along with sodium hypophosphite and hydrogen gas.

17. Write the molecular formula and one use of:

    1. Borax
    Answer:

    Molecular Formula: Na₂B₄O₇ · 10H₂O

    Use: Borax is used in laundry and household cleaning products as a water softener and stain remover.

    2. Hypo
    Answer:

    Molecular Formula: Na₂S₂O₃ · 5H₂O

    Use: Hypo (sodium thiosulfate) is used in photography as a fixing agent to remove unexposed silver halide from photographic emulsions.

    3. Boric acid
    Answer:

    Molecular Formula: H₃BO₃

    Use: Boric acid is used as an antiseptic, insecticide, flame retardant, neutron absorber, or precursor to other chemical compounds.

    4. Carborundum
    Answer:

    Molecular Formula: SiC

    Use: Carborundum (silicon carbide) is used as an abrasive for cutting, grinding, and polishing, as well as in refractories, ceramics, and electric heating elements.

    5. Silica gel
    Answer:

    Molecular Formula: SiO₂ · nH₂O

    Use: Silica gel is used as a desiccant to control humidity and prevent the growth of mold and mildew in various products such as food packaging, electronics, and pharmaceuticals.

18. Why are noble gases chemically inert? Write two uses of noble gases.

    Answer:

    Noble gases are chemically inert because they have a full outer electron shell, making them stable and unlikely to react with other elements. This configuration satisfies the octet rule, where atoms tend to gain, lose, or share electrons to achieve a stable electron configuration. Two uses of noble gases are:

    • Helium is used in cryogenics for its low boiling point and in balloons and airships for its low density.
    • Argon is used in welding to provide an inert atmosphere and in light bulbs to prevent the filament from oxidizing.

19. What are the major pollutants for photochemical smog? Write its major effects.

    Answer:

    The major pollutants for photochemical smog are nitrogen oxides (NOx) and volatile organic compounds (VOCs), which are primarily emitted by vehicles and industrial processes. When these pollutants react with sunlight, they form ozone and other secondary pollutants. The major effects of photochemical smog include respiratory problems, eye irritation, and reduced visibility.

20. How do oxides of sulphur (SO₂) and nitrogen responsible for acid rain? Write the major effects of acid rain.

    Answer:

    Oxides of sulphur and nitrogen, particularly sulfur dioxide (SO₂) and nitrogen oxides (NOx), are major contributors to acid rain. These gases are released into the atmosphere from burning fossil fuels, primarily from vehicles and industrial processes. In the atmosphere, they react with water, oxygen, and other chemicals to form sulfuric acid (H₂SO₄) and nitric acid (HNO₃). Acid rain has several detrimental effects, including damage to forests, aquatic ecosystems, and buildings, as well as the leaching of nutrients from soil.

21. What is the greenhouse effect? How does CFC deplete the ozone layer?

    Answer:

    The greenhouse effect is a natural process that warms the Earth's surface. It occurs when certain gases in the Earth's atmosphere (greenhouse gases) trap heat from the sun, preventing it from escaping back into space. This process is essential for life on Earth, as it keeps the planet's temperature within a range suitable for life. However, human activities, such as burning fossil fuels and deforestation, have increased the concentration of greenhouse gases in the atmosphere, leading to enhanced greenhouse effect and global warming.

    CFCs (chlorofluorocarbons) are synthetic compounds that were widely used in refrigeration, air conditioning, and aerosol propellants. When released into the atmosphere, CFCs eventually reach the stratosphere, where they are broken down by ultraviolet (UV) radiation, releasing chlorine atoms. These chlorine atoms then catalyze the breakdown of ozone (O₃) molecules, leading to the depletion of the ozone layer. The ozone layer is important because it absorbs the majority of the sun's harmful UV radiation, protecting life on Earth from its damaging effects.

22. Reaction of ammonia with:-
    1. CO₂ gas
    2. Cl₂ gas
    3. CuSO₄ soln
    4. Na-metal
    5. CuO
    6. Mercurous nitrate/chloride paper.
23. Reaction of nitric acid with:-
    1. Zn
    2. Mg
    3. Cu
    4. Fe
    5. I₂
    6. P₄
24. Reaction of CO with :
    1. Ni
    2. Cl₂
    3. NaOH
    4. Water gas (CO+H₂) is heated over ZnO+Cu.
25. Reaction to show that:
    1. H₂SO₄ as: - (a) an acid (b) an oxidizing agent (c) dehydrating agent
    2. SO₂ as an oxidizing agent
    3. H₂S as : (a) a reducing agent (b) an analytical reagent.

Metal Chemistry

1. ‘Every ore is a mineral, but every mineral is not ore’, give reason.

2. Write differences with examples between:
   1. Calcination and Roasting.
   2. Pyrometallurgy and electrometallurgy.
   3. Flux and Slag.
3. Write a short note on:
   1. Froth floatation process.
   2. Carbon reduction process.
   3. Aluminothermite process.
4. Explain why:
   1. Carbon reduction process is not applied for the extraction of alkali metal.
   2. Alkali metals impart characteristic color to the flame.
   3. Sodium metal gets tarnished in the air.
   4. Quicklime produces a hissing sound when added into cold water.
   5. Sodium metal is kept in kerosene.
   6. Sodium fire at the laboratory is not extinguished by adding water.
5. Define the terms:
   1. Dead burnt plaster.
   2. Setting of plaster of Paris.

6. Write important characteristics of alkali metals and alkaline earth metals.

7. Write the molecular formula and one use of: washing soda, baking soda, caustic soda, and soda ash.

8. Convert:
   1. Caustic soda to washing soda and baking soda.
   2. Sodium into washing soda.
   3. Sodium into sodium silicate.
   4. Washing soda into soda ash.
9. Action of sodium (Na) with:
   1. Water.
   2. NH₃.
   3. Moist air.
10. Action of caustic soda (NaOH) with:
    1. Phosphorus.
    2. CO₂.
    3. Sulphur.
    4. Zinc.
    5. Ammonium chloride.
11. Action of washing soda (Na₂CO₃) with:
    1. Air.
    2. Heated sand (SiO₂).
    3. Heat.
    4. CaCl₂.

Organic Chemistry

1. Give Reason:

   1. Sodium extract (Lassaigne’s extract) is alkaline in nature.
   Answer:

   The alkalinity of sodium extract is due to the presence of sodium hydroxide (NaOH) formed when sodium reacts with water during the extraction process.

   2. Sodium extract is boiled with conc. nitric acid while testing for halogens.
   Answer:

   Boiling sodium extract with concentrated nitric acid oxidizes any halogens present in the extract to their respective halides, which can then be tested for using specific tests.

2. Give the functional isomers with IUPAC Name of:

   1. C₃H₈O.
   Answer:

   Two functional isomers of C₃H₈O are:

   • Propan-1-ol (1-propanol)
   • Propan-2-ol (2-propanol or isopropyl alcohol)
   2. C₃H₆O.
   Answer:

   Two functional isomers of C₃H₆O are:

   • Propenal (acrolein)
   • Propen-1-ol (1-propenol)
   3. C₃H₆O₂.
   Answer:

   Two functional isomers of C₃H₆O₂ are:

   • Propanoic acid (propionic acid)
   • Methyl ethanoate (methyl acetate)

3. What are electrophiles and nucleophiles? Write two examples of each.

   Answer:

   Electrophiles are electron-deficient species that can accept a pair of electrons. Nucleophiles are electron-rich species that can donate a pair of electrons. Examples:

   • Electrophiles: \( \text{H}^+ \) (proton), \( \text{Br}_2 \) (bromine).
   • Nucleophiles: \( \text{OH}^- \) (hydroxide ion), \( \text{NH}_3 \) (ammonia).

4. Define inductive effect and give its important application.

   Answer:

   The inductive effect is the polarizing effect of a substituent in a molecule, leading to the displacement of electrons along a chain of atoms. An important application is in determining the reactivity of organic compounds.

5. Define an anti-knocking agent (Gasoline additive) and write one example.

   Answer:

   An anti-knocking agent is a gasoline additive that reduces engine knocking in internal combustion engines. Example: Tetraethyl lead (TEL).

6. What is the function of TEL in gasoline?

   Answer:

   TEL, or tetraethyl lead, is added to gasoline to improve its octane rating, which reduces engine knocking and allows for higher compression ratios in internal combustion engines.

7. Define octane number. A fuel has an octane number of 80. What does it mean?

   Answer:

   The octane number is a measure of the resistance of a fuel to knocking in a spark-ignition internal combustion engine. A fuel with an octane number of 80 indicates that it has the same knocking resistance as a mixture of 80% iso-octane and 20% heptane.

8. What is cracking of petroleum?

   Answer:

   Cracking of petroleum is a process in which large hydrocarbon molecules in crude oil are broken down into smaller, more useful molecules. This process is typically done at high temperatures and pressures or in the presence of a catalyst. Cracking is used to produce more valuable products such as gasoline, diesel, and jet fuel from heavier, less valuable crude oil fractions.

9. a) Bromoethane is heated with sodium metal in the presence of dry ether.

   Answer: This reaction results in the formation of ethene (ethylene) and sodium bromide.

10. b) Sodium acetate (sodium ethanoate) is heated with soda-lime.

    Answer: This reaction results in the formation of methane gas.

11. c) 2-bromopropane is heated with alc. KOH.

    Answer: This reaction results in the formation of propene (propylene).

12. d) Ethene (ethylene) is passed through Baeyer’s reagent (Alkaline solution of KMnO₄).

    Answer: Ethene decolorizes Baeyer’s reagent, turning it from purple to colorless, indicating the presence of a double bond.

13. e) Ethyne (acetylene) gas is passed through an ammoniacal solution of silver nitrate.

    Answer: Silver acetylide is formed, which is a white precipitate.

14. Write one example of each:
    1. Kolbe’s reaction.
    2. Dehydrohalogenation reaction.
    3. Decarboxylation reaction.
    Answer:

    1. a) Kolbe’s reaction.

       Example: The electrolysis of potassium salt of carboxylic acid (e.g., potassium acetate) leads to the formation of alkanes with an even number of carbon atoms.

       The electrolysis of potassium acetate:

       \[ 2CH_3COOK \rightarrow (CH_3CO)_2 + 2CH_3COOK \]

    2. b) Dehydrohalogenation reaction.

       Example: The reaction of 2-bromopropane with alcoholic KOH to form propene.

       The reaction of 2-bromopropane with alcoholic KOH:

       \[ CH_3CHBrCH_3 + KOH \rightarrow CH_3CH=CH_2 + KBr + H_2O \]

    3. c) Decarboxylation reaction.

       Example: The heating of sodium salt of ethanoic acid (sodium acetate) with soda-lime to produce methane gas.

       The heating of sodium acetate with soda-lime:

       \[ CH_3COONa + NaOH \rightarrow CH_4 + Na_2CO_3 \]