The repeating unit present in asbestos is
Answers
It's licensing unit present in asbestos.
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Correct question:
The repeating unit present in asbestos is
(a) [Si4O11]6-
(b) [SiO4]4-
(c) [Si2O7]2-
(d)[Si3O9]3-
Answer: (a) [Si4O11]6-
Explanation:
Asbestos (/ æsˈbɛstɒs, æz-, -təs /) [1] is a naturally occurring silicate mineral. There are six types, all made of long and thin crystals with fibers, each fiber is made up of many small "fibrils" that can be released into the atmosphere through abrasion and other processes. Inhaling asbestos fibers can lead to a variety of dangerous lung conditions, including mesothelioma, asbestosis, and lung cancer, so it is now widely known as a major health and safety hazard. [2]
Archaeological studies have found evidence that asbestos was used long ago as a Stone Age to fortify clay pots, [3] but large mines began in the late 19th century when manufacturers and builders began using asbestos for its desirable physical properties. Asbestos is an excellent electrical protection and is highly resistant to fire, so much of the 20th century was widely used worldwide as a building material, until its adverse effects on human health were widely accepted in the 1970s. [4] [5] Many modern buildings built before the 1980's are thought to contain asbestos. [6]
The use of asbestos in construction and fire prevention has been made illegal in many countries. [2] Despite this, at least 100,000 people are estimated to die each year from asbestos exposure-related diseases. In part, this is because many older buildings still contain asbestos; in addition, the effects of exposure can take decades to develop. [6] [7] The most common diseases associated with chronic asbestos exposure are asbestosis (lung scars due to inhalation of asbestos) and mesothelioma (a type of cancer). [8]
Many developing countries still support the use of asbestos as a building material, and asbestos mining continues, as Russia's top producer has an estimated production of 790,000 tons by 2020. [9]
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