Calcium carbonate reacts with water!
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I would like to know whether calcium carbonate reacts with water to produce calcium hydroxide under normal temperature and pressure, and whether it has a strong corrosive effect on ordinary steel plates.
I remember learning in high school that when carbon dioxide is passed through clear lime water (a small amount of calcium hydroxide), calcium carbonate precipitate is formed. However, if carbon dioxide is continued to be passed in after all the calcium hydroxide has been reacted with, calcium bicarbonate is formed, and the white precipitate disappears. When exposed to the atmosphere at normal temperature and pressure for an extended period of time, calcium hydroxide will react; I don’t think it will cause corrosion.
It’s unlikely to happen, mainly because the solubility of calcium carbonate in water is lower than that of calcium hydroxide, so the reaction will not take place!
This phenomenon can be explained using chemical principles: calcium carbonate reacts with water to produce calcium hydroxide under normal temperature and pressure. Lime is formed when calcium carbonate reacts with water to yield calcium hydroxide, and a large amount of heat is released in the process. The calcium hydroxide produced is a moderately strong base, possessing the typical properties of bases; therefore, it has a strong corrosive effect on steel plates.
Calcium carbonate does not react at normal temperature and pressure because 2CaCO3 + 2H2O → Ca(HCO3)2 + Ca(OH)2 is a reversible reaction. The person upstairs said that lime is calcium carbonate from which calcium hydroxide is formed when water is added; this concept is incorrect. The reaction you mentioned is: CaO + H2O → Ca(OH)2
What was said upstairs is correct; calcium carbonate is limestone, which is the main component of marble. Does marble react with metal? Can marble react with water?
There is dissolved carbon dioxide in water, and when it reacts with calcium carbonate, calcium bicarbonate is formed. Since bicarbonate ions undergo hydrolysis to produce calcium hydroxide, this process can cause corrosion over time
Calcium carbonate can exist in the following forms: aragonite, calcite, chalk, limestone, marble, and travertine. It effervesces and dissolves when exposed to dilute acetic acid, dilute hydrochloric acid, or dilute nitric acid. Under high temperatures, it decomposes into calcium oxide and carbon dioxide, but it does not react with water at normal temperature and pressure, remaining as a white precipitate. If water contains a large amount of carbon dioxide, or if it is a carbon dioxide solution, calcium carbonate will dissolve to form calcium bicarbonate.
Calcium carbonate is only slightly soluble in water; how could it react at room temperature?
Logically, it shouldn’t react; calcium carbonate is a quite stable compound! Of course, after hundreds or thousands of years, changes may still occur; it’s just that we won’t have the chance to see them! Hehe:lol
Your knowledge of chemistry is too limited. Calcium carbonate is an extremely stable substance; the rocks we often see on mountains are primarily composed of calcium carbonate, and they remain almost unchanged over thousands of years under natural conditions. Otherwise, nature would be in a completely different state
What was said on the 5th floor is correct; the person on the 4th floor didn’t even know that the component of lime is CaO. They really need to study more carefully*.
Physical chemistry teaches us that every reaction reaches an equilibrium point; theoretically, a system consisting of calcium carbonate and water should contain hydroxide ions. Moreover, the entire system should be in a nearly neutral environment. However, this is probably not the main cause of steel plate corrosion. Steel undergoes oxygen absorption corrosion in weak acidic or neutral conditions, and hydrogen evolution corrosion in acidic conditions.
Since the reaction is reversible, in theory water can also participate in the reaction. However, for the reaction Ca(OH)2 + CO2 = CaCO3 + H2O (the rate of the forward reaction is K1, while the rate of the reverse reaction is K2), at normal temperature and pressure K1 is much larger than K2; therefore, calcium carbonate does not react with water. Calcium carbonate is slightly soluble in water. Calcium carbonate is weakly alkaline in water and does not possess strong corrosive properties toward ordinary steel plates; however, it can still cause corrosion to steel plates in the presence of water. However, the calcium carbonate attached to the plate affects the heat transfer properties of the steel. :lol
The solubility product of calcium carbonate at normal temperature and pressure is 4.96X10-9, while that of calcium hydroxide is 5.5X10-6; it is evident that calcium carbonate does not react with water to form calcium hydroxide under normal temperature and pressure conditions. A saturated solution of calcium hydroxide has a very high alkalinity, with a pH value above 12. In such an environment with high alkalinity, a dense film of iron hydroxide forms on the surface of the steel plate, causing it to enter a passivated state and thus preventing corrosion. Calcium carbonate is a slightly soluble compound; its saturated solution has a pH value of 9, which is far below the value of 11.5 required for steel plates to remain in a passivated state. As a result, the steel plates will corrode very quickly.
Calcium carbonate and water cannot produce calcium hydroxide, but the so-called corrosion mentioned by the poster should be considered from an electrochemical perspective.
CaCO3 does not react with water; it dissolves in water. According to the \"Corrosion Data and Selection Manual\" for carbon steel and cast iron: the annual corrosion rate at a 10% concentration is 0.05–0.5 mm, while at a 100% concentration it is less than 0.05 mm.