Portland cement contains ‘X’ to enhance the setting time. What is ‘X’?
\(CaSO_4.\frac 12 H_2O\)
\(CaSO_4.2H_2O\)
\(CaSO_4\)
\(CaCO_3\)
The Correct Option is B
Solution and Explanation
When mixed with water, the setting of cement takes place to give a hard mass.
This is due to the hydration of the molecule of the constituents and their rearrangement. The purpose of adding gypsum \((CaSO_4.2H_2O)\) is only to slow down the process of setting of the cement so that it gets sufficiently hardened.
So, the correct option is (B): \(CaSO_4.2H_2O\)
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Concepts Used:
S-Block Elements
S-block elements, also known as alkali and alkaline earth metals, constitute the first two groups of the periodic table.
Group 1 elements, including hydrogen, lithium, sodium, potassium, rubidium, cesium, and francium, are alkali metals characterized by low density, high reactivity, and the ability to form strong bases when combined with water. They showcase a single valence electron in their outermost shell, making them eager to lose it in chemical reactions.
Group 2 elements, beryllium, magnesium, calcium, strontium, barium, and radium, make up the alkaline earth metals in Group 2. These metals share similar properties, such as higher densities and melting points compared to alkali metals. They also have a tendency to form ionic compounds with nonmetals.
S-block elements play vital roles in various industrial and biological processes. Alkali metals find applications in batteries, while alkaline earth metals are crucial for construction materials and are essential nutrients for living organisms. Despite their importance, the reactivity of alkali metals requires careful handling, often stored in oil to prevent reactions with moisture or oxygen. Overall, s-block elements contribute significantly to the diverse applications of chemistry in our daily lives.