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Which of the following is used in the manufacture of heat resistance borosilicate glass?A. Boron sesquioxideB. BoraxC. Boric acidD. All of these |
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Answer» Correct Answer - D About `35%` of `B` production is used to manufacture borosilicate glass. Conventional soda glass suffers from thermal shock, i.e., when a piece of glass is heated strongly, the outside becomes hot and tries to expands, while the inside is still cold because glass is such a poor conductor of heat. As a result of stress between the outside and the inside, the glass cracks. When `Na` ions in the glass structure are replaced by `B` atoms, the degree of glass expansion (more precisely called thermal expansivity) is less than half that of conventional glass. As a result, containers made of borosilicate glass, sold under trademarks such as pyrex `(R)`, are capable of being heated without great danger of cracking. |
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