The correct answer is: B. Hydration and dissociation of water.
Cement is a powder that is made from limestone, clay, sand, and iron ore. When cement is mixed with water, it forms a paste. This paste hardens over time to form concrete. The hardening of concrete is a chemical reaction
called hydration. During hydration, the cement particles react with water to form new compounds. These new compounds are what give concrete its strength.The hydration process is also accompanied by the dissociation of water. This means that the water molecules break apart into hydrogen and oxygen ions. These ions play an important role in the hydration process. They help to form the new compounds that give concrete its strength.
The options A, C, and D are incorrect. Dehydration is the opposite of hydration. It is the process of losing water. Dissociation of water is the process of breaking water molecules apart into hydrogen and oxygen ions. Polymerization is the
process of forming large molecules from smaller molecules. None of these processes are involved in the hardening of concrete.