Chemistry MCQs

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Sodium thiosulfate is an important inorganic salt with several medical uses. It is also called sodium hyposulfite or ‘hypo’. It is used in several pharmaceutical preparations and also has various medical properties. 

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Urea is an organic compound with the formula (NH2)2CO. The Nitrogen present in Urea is in the form of Amide. This compound is highly soluble in water and is a very effective source of Nitrogen for plants. It is the main nitrogenous end product of the metabolic breakdown of proteins in all mammals and some fishes.

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Platinum is a naturally white metal. It doses not need to be alloyed for color. Due to its appearance as white, it is commonly known as White Gold.

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Water at 4 degrees Celsius has maximum density. This is due to the unique molecular structure of water, which allows it to reach its highest density at this temperature. As water cools from higher temperatures, it becomes denser until it reaches 4 degrees. below this temperature, it begins to expand, making ice less dense than liquid water. This phenomenon is crucial for aquatic life, as it allows ice to float, insulating the water below.

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The correct statement is that in an alkaline battery, the negative terminal is made of zinc powder, the positive terminal is made of manganese dioxide, and the electrolyte is potassium hydroxide (KOH). Alkaline batteries are known for their long shelf life and higher energy density compared to zinc-carbon batteries. They were invented in the 1950s and are widely used in household devices.

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The Carbon Group of the periodic table includes the elements carbon, silicon, germanium, tin, lead, and flerovium. These elements have four electrons in the outermost shell. Selenium, however, is not a part of this group. It is a member of the Chalcogens and sits beneath Oxygen in the periodic table. The element number for Selenium is 34. It is known for its photovoltaic and photocatalytic properties.

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The main constituent of vegetable oil and animal fats is triglyceride. Triglycerides are composed of three fatty acids linked to a glycerol molecule. They are the most common type of fat found in the body and serve as a major energy source. In fact, triglycerides account for about 95% of the fats in the human diet.

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Aluminum is considered a “Green Metal” primarily due to its high recycling rate. Approximately 75% of all aluminum ever produced is still in use today, as it can be recycled indefinitely without losing quality. This process saves energy—recycling aluminum uses about 95% less energy than producing new aluminum from bauxite ore. Additionally, recycling reduces greenhouse gas emissions and conserves natural resources, making aluminum a sustainable choice in various applications.

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Please note that the Cycloalkanes with more than 20 carbon atoms are called Cycloparaffins. The cycloalkanes have the same properties as the alkanes but they have `Higher Boiling & Melting points`. This is because of the stronger dispersion forces between the atoms known as London Forces.

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Strontium-90 is a “bone seeker” that exhibits biochemical behaviour similar to calcium, the next lighter Group 2 element. After entering the organism, most often by ingestion with contaminated food or water, about 70–80% of the dose gets excreted. Virtually all remaining strontium-90 is deposited in bones and bone marrow, with the remaining 1% remaining in blood and soft tissues. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukaemia.