NIOS Class 12th Chemistry (313): NIOS TMA Solution

NIOS Solved TMA 2024


(i) All questions are compulsory. The marks allotted for each question are given at same place.

(ii) Write your name, enrollment number, Al name and subject on the top of the first page of the answer sheet.

1. Answer any one out of the following questions in about 40 to 60 words

(a) Identify the group and valency of the element having atomic number 119. Also, predict the outermost electronic configuration and write the general formula of its oxide.

Answer- Based on the atomic number 119, this element is known as Ununennilium (symbol Uue), which is a temporary and unstable element. Its external electronic configuration or electron configuration is not known because it is a temporary and unstable element, and its external electronic configuration is undefined. There is no general rule for its electronic structure as it is an experimental element, and its properties can vary over time.

(b) Electron gain enthalpy of chlorine has more negative value as compared to that of fluorine (F), explain the reason.

Answer- The electron gain enthalpy (electron affinity) of chlorine is more negative compared to that of fluorine because chlorine has a higher atomic number, which means it has more protons in its nucleus. This higher proton count results in a stronger attractive force for incoming electrons, making it easier for chlorine to accept an additional electron. This is why the electron gain enthalpy of chlorine is more negative than that of fluorine.

2. Answer any one out of the following questions in about 40 to 60 words.

(a) How do metallic and ionic substances differ in conducting electricity?

Answer- In electrical conduction, there are significant differences between metallic and ionic substances. Metallic substances conduct electricity through the movement of free electrons within a conductive path. On the other hand, ionic substances conduct electricity by facilitating the movement of ions through chemical reactions, which alter their electrical properties. Metallic substances serve as electrical conductors, while ionic substances play a crucial role in processes such as ion transport and electrochemical reactions.

(b) What is a unit cell? How many atoms are there in a FCC unit cell

Answer– A unit cell is the smallest repeating structural unit that cannot be further subdivided. In an FCC (Face-Centered Cubic) unit cell, there are 4 atoms. Each atom is located at the corners of a cube, and an additional atom is located at the center of each of the 6 faces. The FCC unit cell is primarily found in the crystalline structure of metallic elements.

3. Answer any one out of the following questions in about 40 to 60 words.

(a) The enthalpy change for the transition of liquid water to steam at temperature 373K is 40.8 UJ mol-1. Calculate the entropy change for the process.

Answer– For the vaporization of water at 373K, with a given enthalpy change (ΔH) of 40.8 UJ/mol, the entropy change (ΔS) can be calculated using the formula:

ΔS = ΔH / T

ΔS = (40.8 UJ/mol) / (373 K) = 0.109 UJ/(mol·K)

For this process, the entropy change for water vaporization is 0.109 UJ/(mol·K).

(b) Name two factors which favor a spontaneous reaction.

Answer- Two factors that favor a spontaneous reaction are:

  1. Negative Gibbs Free Energy (∆G): A reaction with a negative change in Gibbs free energy (∆G) is spontaneous. When ∆G is negative, it indicates that the products have lower free energy than the reactants, and the reaction will proceed without requiring external energy input.
  2. Increased Entropy (S): An increase in entropy (∆S) favors spontaneity. If a reaction results in a higher degree of disorder or randomness, it is more likely to be spontaneous as nature tends towards greater disorder.

4. Answer any one out of the following questions in about 100 to 150 words.

(a) Define water pollution; list any three anthropogenic sources of water/pollution

AnswerDefinition of Water Pollution: Water pollution is a type of pollution in which there is an undesirable change in water sources, resulting in a reduction in water quality or an adverse impact on the use of water.

Three human-made sources of water pollution:

  1. Industrial Pollution: Pollution is generated from various industrial processes, industrial units, and factories. It includes different forms of chemical industrial pollution, as well as pollution from activities like mining and mineral extraction.
  2. Agricultural Pollution: Pollution originates from agriculture, including the use of chemicals for crop control and excessive use of water resources.
  3. Urban Services Pollution: Water pollution in urban areas comes from domestic and industrial sources, including sewage, sanitation, and the discharge of pollutants into natural water bodies.

(b) A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.

(1) What is the initial effect of the change on vapour pressure?

Answer- The initial impact of a sudden increase in the volume of a sealed container containing a liquid with its vapor in equilibrium at a constant temperature will depend on how the change in container volume is accompanied:

  • If the container’s volume increases, but the amount of liquid inside remains the same, there will be no initial effect on vapor pressure. The amount of vapor and pressure will remain unchanged.
  • If the container’s volume increases, and the amount of liquid is also increased (additional liquid is added to the container), there will be an initial impact on vapor pressure. This can result in an increase in vapor pressure due to the addition of more liquid, affecting its specific qualities and characteristics.

(ii) How do rates of evaporation and condensation change initially?

Answer– When the volume of a sealed container suddenly increases at a certain temperature, the initial effect on vapor pressure can be an increase. This may be due to changes in the balance between the speed and pressure of the vapor in your confined liquid with the sudden change in the container’s volume.

5. Answer any one out of the following questions in about 100 to 150 words.

(a) Write the name of any one metal which can be refined by distillation method

Answer- One of the most well-known metals that can be extracted through the dissolution process (known as leaching) is “Gold.” Gold is a noble, precious metal that can be separated from ore through the dissolution method.

The distinctive feature of gold is that it can be easily leached in a solution made with air, water, and a weak acid. This results in the creation of a gold solution or a gold-bearing solution. Subsequently, gold can be recovered from this solution by boiling it and separating the gold from the solution with the help of air or other suitable reagents, resulting in the precipitation of gold.

Due to its historical significance and its appeal to royalty and nobility, gold has played a vital role throughout history and continues to be essential in jewelry and financial transactions. The various methods of gold leaching have been developed and perfected over time to extract gold efficiently and economically from its ores.

(b) Describe the electrolytic refining method with labeled diagram of copper metal. Write the name of metal which is settled as anode mud.

Answer- The electrical deposition of copper is a scientifically understood process known as electroplating, in which copper compounds like copper sulfate or copper nitrate are electrolyzed to separate copper into different components.

In this process, a copper electrode, often referred to as the “cathode,” is placed in an extremely concentrated aqueous solution. The other electrode, an “anode,” is often made of an inert metal.

When the electroplating process begins, copper is deposited on the suitable metal (cathode) while impurities or rarefied elements in the solution collect naturally in the anode.

The copper is then removed and cleaned, and it can be obtained in a metallic form for various applications.


Why are chromium oxide (Cr2O3 ) and manganese oxide (Mn3O4 ) reduced by aluminium metal power instead of carbon? Write the name of that process and chemical equations related to reduction of above metal oxides

Answer- The process of reducing chromium oxide (Cr₂O₃) and manganese oxide (MnO₄) by aluminum (Al) powder instead of carbon is known as the “Thermite Process” or “Thermite Reduction.” In this process, chromium and manganese oxides are reacted with aluminum at high temperatures, resulting in the reduction of chromium and manganese. The thermite equations are as follows:

Chromium Oxide Reduction: 2Cr₂O₃ + 4Al → 3Cr + 2Al₂O₃

Manganese Oxide Reduction: 3MnO₄ + 4Al → 3Mn + 2Al₂O₃

The thermite process occurs at high temperatures and rapidly increasing pressure. As a result, it leads to the reduction of chromium and manganese, allowing them to be obtained in their metallic form with high quality. The thermite process is often used in various industries and applications where high heat and metal reduction are required.

6. Prepare any one of the project out of two given below in about 500 words

(a) You have visited a hospital of you town. You have found that some people were suffering from higher, and some have minor injuries, while you are also patient of hyper acidity and cold. Doctors prescribed different medicines to all the patients.

(i) What are the names of antipyretic drugs? (One drug)

Answer- “Antipyretic medications,” also known as “fever-reducing drugs,” are used to treat viral fevers (such as influenza and dengue) or bacterial fevers (such as malaria). Some of the prominent names among them include:

Paracetamol (Acetaminophen): It helps in reducing the symptoms of fever and controlling body temperature.

Aspirin: Aspirin is used to relieve fever and pain, but it should not be taken by children and pregnant women.

Ibuprofen: It can help reduce fever and inflammation.

Please note that these medications should only be taken under the advice of a doctor and it is essential to use them in the correct dosage. Consult your healthcare provider for personalized health-related guidance.

(ii) Write the name of an antiseptic medicine.

Answer- The name of an antiseptic medication is “Antiseptic.” Antiseptics are a type of medication designed to protect against infections caused by bacteria, microorganisms, and other pathogens. These medications are available in various forms, such as solutions, creams, ointments, and liquid antiseptics. Antiseptic medications are commonly used in hospitals, clinics, and medical settings to prevent the spread of infections. They are prescribed by healthcare professionals to help in the prevention of bacterial infections and to maintain personal health and hygiene by providing protection against various disease-causing organisms.

(iii) Names of two antacids?

Answer- Two antacids/antacid medications are:

  1. Ranitidine: This is an antacid medication that helps in reducing excessive acidity in the stomach. It belongs to the H2-receptor antagonists class of drugs and is used in the treatment of conditions like peptic ulcers, gastroesophageal reflux disease (GERD), and other stomach-related disorders.

  1. Proton Pump Inhibitors (PPIs): These antacid medications include drugs like Omeprazole, Lansoprazole, Esomeprazole, Rabeprazole, and Pantoprazole. They are used to reduce excessive stomach acidity and are employed in the treatment of conditions such as peptic ulcers, gastritis, and esophagitis.

These medications are used to alleviate symptoms of stomach acidity and related disorders, but it is essential to use them under a doctor’s guidance and follow their prescribed directions.

(iv) Write the name of one antihistamine.

Answer- A prominent physicist named “Navel Armstrong” is associated with an antiparticle. He made significant contributions to the field of science in the 20th century. He was known for his research in electromagnetism, electrical conductivity, and various types of radiation. In 1904, he was awarded the Nobel Prize for his work on electrical conductivity. He made important discoveries in the field of physics and is remembered for his contributions to the scientific community.

(v) Quinine is the very common medicine of which type of fever?

Answer-Cinnarizine is a widely used medication that is used to treat migraine. It is an anti-dopaminergic and antihistamine drug, meaning it can modify brain chemistry and reduce anxiety, helping to control migraine headaches. Cinnarizine is used to alleviate the symptoms of migraine and associated distress and confusion.

(vi) What type of damage to body is possible if you are using phenol more than 1% concentrate

Answer- The use of phenol concentration greater than 1% in the body can cause significant harm. Phenol is a toxic and highly corrosive chemical that, when present in excessive concentrations, can be detrimental to health. It can damage organs such as the kidneys, brain, and other body tissues, leading to symptoms such as vomiting, pain, and an increased risk of cancer. High concentrations of phenol in the body are not safe for health.

(b) Visit the nearby treatment process of Sewage and collect the following knowledge/ information.

(i) How many stages are there of treatment of waste water?

Answer- The treatment of wastewater, especially municipal and industrial wastewater, involves a four-stage process:

  1. Primary Treatment: In this stage, wastewater is collected, and large solids are separated through physical processes like sedimentation.
  2. Secondary Treatment: After primary treatment, the partially treated water undergoes biological processes that break down organic matter and remove dissolved and suspended solids.
  3. Tertiary Treatment: This stage further purifies the water through advanced physical and chemical processes, reducing contaminants like nutrients and pathogens.
  4. Quaternary Treatment: If necessary, treated water may be safely discharged or reused for various purposes, following appropriate safety measures.

These four stages ensure that wastewater is effectively and safely treated before its final discharge or reuse.

(ii) What is coagulation?

Answer- Skanda, also known as Kartikeya or Murunga, is an important deity in Indian mythology and Hinduism. He is considered the son of Goddess Parvati and Lord Shiva and is often depicted with his four consorts: Sati, Uma, Chandrakala, and Vaishnavi. Skanda is also known by various names and titles, such as Kartikeya, Murunga, and Shanduka. He is revered as the god of war, wisdom, and strength, and is often associated with attributes like bravery, valour, and the destroyer of evil forces.

(iii) What is substance?

Answer- A substance, in essence, is a physical or chemical entity that comprises the fundamental constituents of all matter in the universe, including elements and compounds. Substances can exist in various states, such as solid, liquid, or gas, and they possess unique properties, including gravity, thermal conductivity, atomic structure, and molecular quality. In the realm of material science, the analysis and study of substances play a vital role, as they are fundamental to both physics and chemistry.

(iv) What is softening?

Answer- “Softening” is a process aimed at making a material, such as fabric or cloth, soft, pliable, and flexible. It is done to enhance the comfort and usability of the material, often in the production of comfortable clothing, dyeing processes, and the manufacturing of consumer products. Softening works by subjecting the material to the influence of heat and moisture, which can impart flexibility and comfort to the material, making it more pliable and user-friendly.

(v) Which is used as disinfectant to kill bacteria?

Answer- To kill bacteria, antibiotics are used as bactericides, which specifically target and destroy certain types of bacteria. These antibiotics inhibit bacterial growth and division, affecting their life processes, ultimately causing their death. Antibiotics are employed in the treatment of various infections, including bacterial infections. Examples of antibiotics include penicillin, cephalosporins, tetracyclines, and more, and they play a crucial role in medical treatment by combating bacterial infections.

(vi) How chlorine produces toxic and potentially active carcinogens?

Answer- Chlorine can produce chlorinated and potentially reactive carcinogens. An example of this was demonstrated in the past when scientists like Dyestuff reacted chlorine with carbon tetrachloride to synthesize formaldehyde (CH₂O). In this process, chlorine reacts with carbon to produce formaldehyde as a result. The chlorinated compounds generated can be toxic and potentially carcinogenic, with formaldehyde being one of the substances linked to cancer.