All questions of Chemistry for CDS Exam

Bauxite, an aluminium ore, is the world’s main source of aluminium. It consists mostly of the minerals gibbsite.

NH3 and NH3. Both polar, asymmetric molecules. CH4 is nonpolar. CO2 is symetrical.

(a) HF - Hydrogen bonding HCl,HBr,HI→ Dipole-dipole interaction, London-dispersion force.

In a gas, the distance between molecules, whether monatomic or polyatomic, is very large compared with the size of the molecules; thus gases have a low density and are highly compressible.Density: The molecules of a liquid are packed relatively close together. Consequently, liquids are much denser than gases.

The rocks of the Dharwar system are mainly sedimentary in origin and occur in narrow elongated synclines resting on the gneisses found in Bellary district, Mysore and the Aravallis of Rajputana. These rocks are enriched in manganese and iron ore which represents a significant resource of these metals.

Chhattisgarh is the second most coal-producing state. It has 15% coal quantity of the country while it produces 16% coal in the country. The main coalfield of North Chhattisgarh includes Chirmiri, Kursia Bishrampur, Ghilmili, Sonhat, Lakhanpur Sendouorgarh and Ramkola.

Answer :

• Turamdih Uranium deposit is located about 24 km west of Jaduguda.

A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. The hydrogen then has the partial positive charge.

The interaction energy of London force is inversely proportional to sixth power of the distance between two interacting particles but their magnitude depends upon. (d) strength of permanent dipoles in the particles.

Conversion of Chemical Energy into Electrical Energy in a Battery

The correct answer to the question is option 'C' - a battery. A battery is a device that converts chemical energy into electrical energy through a chemical reaction. It consists of one or more electrochemical cells, which are composed of two electrodes (a cathode and an anode) and an electrolyte.

Chemical Reactions in a Battery:

When a battery is connected to an external circuit, a chemical reaction occurs within the battery. This chemical reaction involves the transfer of electrons from the anode to the cathode through the external circuit. The chemical reaction is typically a redox reaction (oxidation-reduction reaction), where one electrode undergoes oxidation (loses electrons) and the other undergoes reduction (gains electrons).

Here is a breakdown of the chemical reactions that occur in a typical battery:

1. Anode Reaction: At the anode, oxidation takes place, and the anode material loses electrons. For example, in a typical alkaline battery, the anode reaction is:

Zn(s) -> Zn2+(aq) + 2e-

In this reaction, zinc metal (Zn) is oxidized to form zinc ions (Zn2+) and release two electrons (2e-).

2. Cathode Reaction: At the cathode, reduction takes place, and the cathode material gains electrons. For example, in a typical alkaline battery, the cathode reaction is:

2MnO2(s) + H2O(l) + 2e- -> Mn2O3(s) + 2OH-(aq)

In this reaction, manganese dioxide (MnO2) is reduced by gaining two electrons (2e-) and reacts with water (H2O) to form manganese(III) oxide (Mn2O3) and hydroxide ions (OH-).

3. Overall Reaction: The overall reaction in a battery is the sum of the anode and cathode reactions. In the case of an alkaline battery, the overall reaction is:

Zn(s) + 2MnO2(s) + H2O(l) -> Zn2+(aq) + Mn2O3(s) + 2OH-(aq)

This overall reaction releases energy in the form of electrical potential energy, which can be harnessed to do work in an external circuit.

Conversion of Chemical Energy to Electrical Energy:

The conversion of chemical energy into electrical energy occurs due to the movement of electrons from the anode to the cathode through the external circuit. This flow of electrons creates an electric current, which can be used to power various devices or perform work.

The chemical reactions in the battery result in a potential difference, or voltage, between the anode and cathode. This potential difference drives the movement of electrons, creating an electric current. The electrical energy produced can then be used to power devices such as flashlights, remote controls, smartphones, and many more.

In summary, a battery converts chemical energy into electrical energy through a redox reaction. The anode undergoes oxidation, losing electrons, while the cathode undergoes reduction, gaining electrons. The movement of electrons through the external circuit creates an electric current, which can be used to power various devices.

Anthracite has a higher percentage of Carbon. It has a carbon content of over 87% on a dry ash-free basis.

Gold is found in the Hutti, Kolar and Ramgiri regions of India.

Khetri, located in the Jhunjhunu district of Rajasthan, is famous for its copper mines. The region has a rich history of copper mining and has been a major source of copper production in India. Here is a detailed explanation of why Khetri is renowned for its copper:

Historical Significance:
- Khetri's association with copper mining dates back to ancient times. The region has been inhabited since the Indus Valley Civilization, and copper artifacts from that era have been discovered here.
- During the Mauryan period, Khetri was an important center for copper production. The excavation of ancient copper mines and smelting sites in the region suggests that copper mining was prevalent during that time.
- The Rajputs, who ruled the region during the medieval period, also recognized the significance of Khetri's copper mines and utilized them for their military and economic endeavors.

Abundance of Copper Deposits:
- Khetri is located in the Aravalli Range, which is known for its mineral-rich deposits. The region has abundant reserves of copper ore, making it an ideal location for mining activities.
- The copper deposits in Khetri are primarily found in the form of copper pyrite (chalcopyrite) and copper glance (chalcocite). These minerals contain a high concentration of copper, making them valuable for extraction.

Modern Copper Mining:
- With the advent of modern mining techniques, Khetri's copper mines witnessed significant development. The Hindustan Copper Limited (HCL), a public sector undertaking, has been instrumental in the extraction and processing of copper in Khetri.
- The Khetri Copper Complex, operated by HCL, consists of mines, concentrators, smelters, and refineries. It is one of the largest copper complexes in India and plays a crucial role in meeting the country's copper requirements.

Economic Importance:
- The copper mining industry in Khetri has contributed significantly to the economic development of the region and the state of Rajasthan.
- It has generated employment opportunities for the local population, both directly and indirectly. Many people are engaged in mining, transportation, and ancillary services related to the copper industry.
- The revenue generated from copper mining has contributed to the overall growth and infrastructure development of the region.

In conclusion, Khetri in Rajasthan is famous for its copper mines. The region's historical significance, abundance of copper deposits, modern mining techniques, and economic importance have collectively made Khetri a renowned hub for copper production in India.

Explanation:

Jaduguda is a small town located in the Singhbhum district of Jharkhand state in India. It is famous for its uranium mines which produce uranium ore, a key component in the production of nuclear energy.

Background:

India is one of the largest consumers of energy in the world, and with a rapidly growing population, the demand for energy is expected to increase significantly in the future. In order to meet this demand, India has been investing heavily in the development of nuclear energy as a clean and sustainable source of power.

Jaduguda is one of the most important uranium mining sites in India, and it is operated by the state-owned Uranium Corporation of India Limited (UCIL). The site was discovered in the late 1950s, and mining operations began in the 1960s. Since then, the site has been a major source of uranium for India's nuclear power plants.

Impact:

The uranium extracted from Jaduguda is used to fuel India's nuclear reactors, which generate electricity for millions of people. Nuclear power is considered to be a clean and efficient source of energy, and it is an important component of India's energy mix. The uranium mining operations in Jaduguda also provide employment and economic opportunities for the local community.

Environmental concerns:

Mining operations can have significant environmental impacts, and there have been concerns about the potential health and environmental risks associated with uranium mining in Jaduguda. The mining and processing of uranium ore can release radioactive materials into the environment, and there have been reports of contamination of groundwater and soil in the area. The UCIL has taken steps to address these concerns, such as implementing safety measures and monitoring the environmental impact of mining operations.

Conclusion:

Jaduguda's uranium mines are an important source of energy for India, and they provide employment and economic opportunities for the local community. However, there are also concerns about the potential environmental and health risks associated with uranium mining operations, and it is important to ensure that appropriate safety measures are in place to protect the environment and the local community.

Coking coal is a vital input in Steelmaking

Coking coal, also known as metallurgical coal, is a crucial raw material in the steelmaking process. It plays a significant role in the production of high-quality steel. Let's delve into the details to understand why coking coal is essential in steelmaking.

1. Steelmaking Process:
- Steelmaking is the process of producing steel from iron ore and other materials.
- It involves the removal of impurities from iron ore to obtain pure iron.
- The pure iron is then mixed with various elements, such as carbon and alloying agents, to create different grades of steel.
- The mixture of iron ore and carbon is heated in a blast furnace to produce molten iron, which is further refined to remove impurities.
- Coking coal is used in the blast furnace as a fuel and a reducing agent to convert iron ore into molten iron.

2. Role of Coking Coal:
- Coking coal is primarily used to produce coke, a high-carbon fuel derived from coal.
- Coke acts as both a fuel and a reducing agent in the blast furnace.
- As a fuel, coke provides the necessary heat energy to sustain the high temperatures required for the steelmaking process.
- As a reducing agent, coke reacts with iron ore, reducing the oxygen content and transforming it into molten iron.
- The carbon content in coking coal is essential for these reactions to occur effectively.
- The coke produced from coking coal also helps in the removal of impurities, such as sulfur, during the steelmaking process.

3. Quality Requirements:
- The quality of coking coal is crucial for efficient steelmaking.
- It should have a high carbon content, low ash content, and low sulfur content.
- The carbon content provides the necessary heat energy and acts as a reducing agent.
- The low ash content ensures minimal impurities during the steelmaking process.
- The low sulfur content prevents the formation of sulfur compounds that can weaken the steel's mechanical properties.

Conclusion:
Coking coal is an indispensable input in the steelmaking industry. It serves as a fuel, a reducing agent, and helps remove impurities during the production of steel. The quality of coking coal directly impacts the efficiency and quality of the steelmaking process. Therefore, it is vital to have a consistent supply of high-quality coking coal for the steel industry to meet its demands and produce high-quality steel products.

Balaghat is known for its Manganese production. About 80% of Manganese production of the country comes from Balaghat. Majhgaon is known for its diamond mines, which is situated in the Panna district of Madhya Pradesh.

Enriched uranium is one in which the percentage of 235U has been artificially increased.

Explanation:
Enriched uranium refers to a type of uranium in which the percentage of the isotope uranium-235 (235U) has been artificially increased. Uranium occurs naturally in the Earth's crust and is composed of three isotopes: uranium-238 (238U), uranium-235 (235U), and uranium-234 (234U). These isotopes have slightly different atomic masses due to variations in the number of neutrons in their nuclei.

Why is uranium enrichment necessary?
Uranium enrichment is necessary for several applications, including nuclear power generation and the production of nuclear weapons. Natural uranium as found in nature typically contains only about 0.7% uranium-235, while the majority is uranium-238. In order to use uranium as fuel in nuclear reactors or to create weapons-grade material, it is necessary to increase the concentration of uranium-235 through a process called enrichment.

The Uranium Enrichment Process:
The process of uranium enrichment involves increasing the concentration of uranium-235 by separating it from uranium-238. There are various methods of enrichment, but the most common one is centrifuge enrichment.

Centrifuge Enrichment:
In centrifuge enrichment, uranium hexafluoride (UF6) gas is fed into a series of high-speed centrifuges. These centrifuges spin at extremely high speeds, causing the heavier uranium-238 to migrate towards the outer edge while the lighter uranium-235 collects near the center. This separation is based on the slight difference in mass between the two isotopes.

Gradual Increase in Uranium-235 Concentration:
Through multiple stages of centrifuge enrichment, the concentration of uranium-235 can be gradually increased. The enriched uranium produced through this process is then used as fuel in nuclear power plants or can be further processed for military purposes.

Conclusion:
Enriched uranium is a type of uranium in which the percentage of uranium-235 has been artificially increased. This is achieved through a process called uranium enrichment, where the heavier uranium-238 is separated from the lighter uranium-235. Enriched uranium is used in various applications, including nuclear power generation and the production of nuclear weapons.

A

Understanding Detergents
Detergents are substances used for cleaning and they play a vital role in various cleaning applications. They can be categorized based on their chemical structure and the type of surfactants they contain.
Types of Detergents
- Sodium Salts of Fatty Acids: These are traditional soaps made from natural fats and oils. They work effectively in soft water but may not perform well in hard water. Thus, they are not classified as synthetic detergents.
- Sodium Salts of Sulphonic Acids: This is the correct answer. Synthetic detergents, commonly used in household and industrial cleaning products, are derived from petrochemicals and often take the form of sodium salts of sulfonic acids. These detergents are effective in hard water, provide better cleaning power, and are designed to work in a variety of conditions.
- Sodium Salt of Benzoic Acid: While this compound can serve as a preservative in food, it is not classified as a detergent. It does not possess the surfactant properties necessary for cleaning applications.
Conclusion
The correct classification of detergents is essential to understand their functionality and application. Sodium salts of sulfonic acids are designed to provide enhanced cleaning capabilities, making option 'B' the correct choice. Their effectiveness in hard water and ability to emulsify oils and dirt are what set them apart from traditional soap-based cleaners.

Understanding Rectified Spirit
Rectified spirit refers to ethanol that has been purified through distillation, resulting in a high concentration of alcohol. When it contains 5% water, it is specifically known as rectified spirit.
Key Characteristics of Rectified Spirit:
- High Purity: Rectified spirit typically contains around 95% ethanol and 5% water, making it a highly concentrated form of alcohol.
- Uses: It is commonly used in laboratories, pharmaceuticals, and industries due to its effectiveness as a solvent and its ability to extract compounds.
- Distillation Process: The process involves distilling fermented liquids to separate alcohol from other components. This leads to the concentration of ethanol.
Comparison with Other Types of Alcohol:
- Denatured Spirit: This is ethanol that has been deliberately rendered undrinkable by adding toxic substances. It is used for industrial purposes and does not contain a specific percentage of water.
- Methylated Alcohol: This typically refers to methanol, which is highly toxic and not suitable for consumption.
- Power Alcohol: This term is used for ethanol blended with gasoline for use as fuel, usually containing more than just 5% water.
Conclusion:
The correct identification of ethanol with 5% water as rectified spirit highlights its purity and specific applications. Understanding these distinctions is crucial for fields such as chemistry and industry, making rectified spirit a valuable substance in both practical and scientific contexts.

Gobar gas, also known as biogas, contains mainly methane (CH4) and carbon dioxide (CO2). Methane is the primary component of biogas and is responsible for its combustible properties. Carbon dioxide is a byproduct of the anaerobic digestion process that produces biogas. In addition to methane and carbon dioxide, small amounts of other gases such as hydrogen sulfide (H2S), nitrogen (N2), and trace amounts of various impurities may also be present in gobar gas.