Chemistry MCQs

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Fermentation is an anaerobic chemical process that breaks down glucose molecules. In baking, yeast consumes sugar and converts it into carbon dioxide and alcohol, making the dough rise. This gas gets trapped in the strands of gluten, resulting in air pockets that cause the dough to rise and form the characteristic spongy texture of bread and cakes. Further, the creation of lactic and acetic acids during fermentation augments this dough handling process, improves flavor, enhances the texture, and extends the shelf-life of the baked products.

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During nuclear fission, a neutron collides with a uranium nucleus and splits it into lighter nuclei, releasing energy and more neutrons. These released neutrons then can strike other uranium nuclei, causing more fission reactions and propagating the chain reaction.

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Marie Sklodowska Curie, born Maria Salomea Sklodowska, was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity. As part of the Curie family legacy of five Nobel Prizes, she was the first woman to win a Nobel Prize, the first person and the only woman to win the Nobel Prize twice, and the only person to win the Nobel Prize in two scientific fields. She was also the first woman to become a professor at the University of Paris. She shared the 1903 Nobel Prize in Physics with her husband Pierre Curie and physicist Henri Becquerel, for their pioneering work developing the theory of “radioactivity” (a term she coined). Using techniques she invented for isolating radioactive isotopes, she won the 1911 Nobel Prize in Chemistry for the discovery of two elements, polonium and radium.

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Iodoform is the organoiodine compound with the formula CHI3. A pale yellow, crystalline, volatile substance, it has a penetrating odor and, analogous to chloroform, sweetish taste. It is occasionally used as a disinfectant. Adolf Hitler’s mother, Klara Hitler, died of iodoform poisoning brought on by her treatment for breast cancer.

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Isobars are (nuclides) atoms of different chemical elements that have the same number of nucleons. They differ in atomic number (number of protons) but have the same mass number. 40S, 40Cl, 40Ar, 40K, and 40Ca are example of a series of isobars. The nuclei of these nuclides all contain 40 nucleons; however, they contain varying numbers of protons and neutrons.

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Soil is an example of a heterogeneous mixture that combines many different elements which are not uniform and are unevenly distributed throughout the composition. No two soil samples have the precise proportions of its inherent components. In contrast, a homogeneous mixture is a solid, liquid or gaseous mixture that has the same proportions of its components throughout a given sample.

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The manufacture of iron ore involves the process of reduction. Important ores of iron : Haematite, Magnetite.

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The main gases responsible for causing acid rain are sulphur dioxide as well as nitrous oxides. The main sources of sulphur dioxide are metal working industries and coal-fired power stations whereas nitrous oxide is from vehicles and fuel combustion.

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Sodium is a very reactive metal. It reacts vigorously both with oxygen and water. A lot of heat is generated in this process. Therefore, it is stored in kerosene to avoid contacts between both atmospheric oxygen and water.

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Cast Iron is a hard, brittle, nonmalleable iron-carbon alloy, cast into shape, containing 2 to 4.5 percent carbon. Steels contain less 0.2% to 2.0% of carbon, while all cast irons contain more than 2% carbon. Wrought iron is an iron alloy with very low carbon (0.04 to 0.08%) content.