Phosphorus and its Compounds MCQ with Answers

Explanation: This question asks about the operating temperature range required in an electric furnace during the extraction of phosphorus, focusing on the thermal conditions needed for efficient chemical transformation. Phosphorus extraction typically involves heating phosphate ores with coke and silica in an electric furnace. This process requires extremely high temperatures to break strong chemical bonds and facilitate reduction reactions. The furnace must provide sufficient Heat to convert Solid reactants into gaseous phosphorus, which is then condensed. At lower temperatures, the reaction remains incomplete, while excessively high temperatures may lead to energy wastage or equipment damage. The process depends on maintaining a controlled high-temperature Environment where silica helps remove impurities and carbon acts as a reducing agent. For example, similar high-temperature conditions are used in Metallurgy when extracting Metals like iron, where Heat drives reduction reactions. Overall, the furnace temperature must be high enough to sustain continuous reduction and vaporization of phosphorus efficiently while ensuring stability of the process.

Explanation: This question focuses on identifying the temperature at which white phosphorus spontaneously catches fire in air, highlighting its highly reactive nature. White phosphorus is known for its low ignition temperature and high reactivity with oxygen. It readily oxidizes when exposed to air, producing Heat that eventually leads to combustion. Because of this property, it must be stored under water to prevent accidental ignition. The ignition temperature reflects the point at which the rate of oxidation becomes rapid enough to produce visible flames. This behavior is due to its Molecular structure, where phosphorus atoms are arranged in a strained configuration, making it unstable and reactive. A relatable example is how dry leaves catch fire more easily than green leaves because they require less Heat to ignite. In summary, white phosphorus ignites at a relatively low temperature due to its unstable structure and strong tendency to react with oxygen in the Atmosphere.

Explanation: This question examines the distinctive odor associated with white phosphorus, which is often used as an identifying physical property in Chemistry. White phosphorus is a highly reactive, waxy Solid that slowly oxidizes when exposed to air, releasing fumes. These fumes contribute to its recognizable smell. The odor is often linked to compounds formed during oxidation, giving it a sharp and noticeable scent. Such sensory properties help chemists identify substances even without advanced instruments. For instance, certain gases like ammonia have a strong, recognizable smell that aids detection. Similarly, the smell of white phosphorus is considered characteristic and is frequently mentioned in laboratory descriptions. Overall, the odor arises due to its interaction with air and formation of volatile compounds, making it a useful qualitative property for identification.

Explanation: This question focuses on understanding the temperature at which white phosphorus changes from liquid to vapor, emphasizing its physical properties. Boiling point depends on intermolecular forces present in a substance. White phosphorus exists as discrete molecules held together by weak van der Waals forces, which require relatively moderate energy to overcome compared to ionic or metallic bonds. When heated, these forces weaken until the substance transitions into vapor. This property is important for processes like distillation and purification. Compared to substances with stronger Bonding, white phosphorus boils at a lower temperature. For example, water requires more energy to boil due to hydrogen Bonding between molecules. In summary, the boiling point of white phosphorus reflects its Molecular structure and the nature of forces holding its molecules together.

Explanation: This question addresses the main chemical composition of bones, which are essential structural components of the human body. Bones are composed of both Organic and Inorganic materials. The Organic part mainly includes collagen, providing flexibility, while the Inorganic portion consists of mineral Salts that give strength and rigidity. Among these Minerals, certain calcium compounds play a dominant role. These compounds form a hard matrix that supports body structure and protects internal organs. The balance between Organic and Inorganic components ensures bones are both strong and slightly flexible. A simple analogy is reinforced concrete, where steel provides flexibility and cement offers strength. Overall, the primary composition of bones involves mineral Salts that contribute significantly to their hardness and durability.

Explanation: This question explores the composition of bone ash, which is the residue left after burning bones at high temperatures. During combustion, Organic components such as collagen are destroyed, leaving behind Inorganic Minerals. The major constituent of this residue is calcium phosphate, which represents the mineral framework of bones. The percentage indicates how much of the bone’s structure is made up of this compound after removing Organic Matter. This value is important in fields like biochemistry and materials science, where bone composition is studied for medical and industrial applications. For instance, similar mineral analysis is used in understanding soil composition or cement materials. In summary, bone ash largely consists of mineral content, with calcium phosphate forming the dominant proportion after combustion.

Explanation: This question focuses on identifying the natural mineral source from which phosphorus is commonly extracted. Ores are naturally occurring materials that contain valuable elements in sufficient quantity for extraction. Phosphorus is not found free in nature due to its high reactivity, so it occurs in combined forms within Minerals. These Minerals are mined and processed to obtain elemental phosphorus or its compounds. The identification of a major ore depends on its abundance and phosphorus content. In industrial Chemistry, selecting the right ore is crucial for efficient extraction and economic viability. For example, iron is commonly extracted from hematite due to its high iron content. Similarly, phosphorus extraction relies on specific mineral ores that are rich in phosphate compounds. Overall, the correct ore is one that serves as a primary commercial source of phosphorus.