Consider the following statements. 1. Pyrex glasses have boron oxide as main constituent besides silica. 2. Pyrex glasses have high thermal expansion, thus less vulnerable to cracking from thermal shock. 3. They are commonly used for reagent bottles, optical component and household cookware. Which of the statement(s) given above is/are correct? A. 1, 2 and 3 B. 1 and 3 C. 2 and 3 D. Only 2

The correct answer is: A. 1, 2 and 3

Pyrex glasses are a type of borosilicate glass, which means that they contain boron oxide in addition to silica. Borosilicate glasses have a higher thermal expansion coefficient than soda-lime glasses, which means that they expand more when heated. This makes them less vulnerable to cracking from thermal shock, which is the sudden change in temperature that can cause glass to break. Pyrex glasses are commonly used for reagent bottles, optical components, and household cookware because of their resistance to thermal shock.

Statement 1 is correct because Pyrex glasses do have boron oxide as a main constituent besides silica. Statement 2 is also correct because Pyrex glasses do have a high thermal expansion coefficient, which makes them less vulnerable to cracking from thermal shock. Statement 3 is also correct because Pyrex glasses are commonly used for reagent bottles, optical components, and household cookware.

Therefore, all three statements are correct.