65th Prelims 2019

Explanation:

Antoine Lavoisier, a French chemist, is widely recognized as the 'Father of Modern Chemistry' due to his work on the law of conservation of mass, naming of oxygen and hydrogen, and helping to systematize chemical nomenclature.

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The mass number is calculated as the sum of protons and neutrons. Given 18 electrons, the number of protons is also 18. Mass number = protons + neutrons = 18 + 20 = 38.

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Nitrous oxide (N2O) is commonly referred to as laughing gas due to its euphoric and anesthetic effects. It is used in medical procedures and dentistry and has a high global warming potential.

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'Gases' is not a classification of elements. Elements are categorized as metals, non-metals, and metalloids based on their chemical and physical properties. Oxygen and nitrogen are gases but are elements.

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Pure water has a neutral pH of 7, indicating a balanced concentration of hydrogen ions and hydroxide ions. Values below 7 are acidic, and above 7 are basic or alkaline.

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Carbon dioxide (CO2) is the main greenhouse gas, trapping heat in Earth's atmosphere and contributing significantly to global warming. Methane, nitrous oxide, and ozone are present in smaller concentrations.

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Kerosene is a hydrocarbon fuel composed primarily of carbon and hydrogen atoms and lacks oxygen. Glass, soil, and cement contain oxygen as part of their chemical composition.

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Natural rubber is a polymer of isoprene (polyisoprene). It is used in tires, gloves, and various rubber products. Styrene, vinyl acetate, and propene form different polymers.

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Glucose is a monosaccharide with chemical formula C6H12O6, consisting of six carbon, twelve hydrogen, and six oxygen atoms. It is a primary energy source for living organisms.

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Carbon monoxide (CO) has a bond order of 3, indicating a triple bond consisting of one sigma and two pi bonds. This results in a short, strong, and stable bond.

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Charles Darwin, an English naturalist, wrote 'The Origin of Species' in 1859, presenting the theory of evolution by natural selection.

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Mutualism is a relationship where both organisms benefit. In lichen, algae produce carbohydrates via photosynthesis, and fungi provide protection and absorb nutrients.

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Habitat refers to the specific location where an organism lives, providing necessary conditions for survival, such as a freshwater pond for fish.

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Chloroplasts in plant cells capture sunlight and convert it into ATP during photosynthesis. Mitochondria generate ATP through cellular respiration, not solar energy directly.

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During photosynthesis, plants produce glucose (sugar) as the primary product and release oxygen (O2) into the atmosphere as a byproduct.

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Osteology is the study of bones, including their structure, function, development, and forensic analysis.

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Lymphocytes are primarily formed in the bone marrow, which produces various blood cells essential for the immune system.

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Thyroxine, produced by the thyroid gland, contains iodine and regulates metabolism and growth.

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AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), which attacks the immune system.

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Sunlight takes approximately 8 minutes to travel from the Sun to the Earth, covering a distance of about 150 million kilometers.