Why, when water boils, does limescale form?

Answer 1

It is because salts in the water come out of solution. According to Wikipedia this is because calcium carbonate salts have the unusual property of being less soluble in hot water than cold but this, of itself would explain why the carbonate doesn't redissolve when the water cools down again. I think that this is a simplified description of the conversion of soluble bicarbonate to insoluble carbonate by boiling which is the major process by which limescale forms. The bicarbonate ion is also known as hydrogen carbonate or HCO3(-) and is the anion of carbonic acid formed when carbon dioxide dissolves in water:
(1) CO2 + H2O = H2CO3
There is also an equilibrium between carbonate and bicarbonate ions in solution:
(2) HCO3 = H(+) + CO3(2-) which depends on pH.
CO2 is less soluble in hot water than cold so when water is boiled dissolved CO2 is driven off, pushing the equilibrium of equation (1) to the left and raising the water pH (from pH 5.7 to 7 for a model system) which pushes the equilibrium of (2) to the right and since carbonate salts are much less soluble than bicarbonate you precipitate calcium or magnesium carbonate as your limescale.

Answer 2

How Does Limescale Form

Answer 3

Limescale forms only in hard water areas. It's the salts that are absorbed from the surrounding rocks around the reservoir. When the water in your kettle is boiled it leaves the "salts" behind as a sediment.

In soft water areas there are no deposits, and your kettle will look brand new for years.

Answer 4

limescale (CaCO3) is just limestone deposits absorbed in to water from the natural limestone it seeps through but it precipitates out at around 50 degres C so all water heaters not just kettles suffer from it even hot taps can "Fur" up esp when a pressure difference is seen high pressure in the pipe low pressure as it leaves the tap the same hapens with stalagtites in cave

Answer 5

distinct aspects have reasonable transformations in voltage and or capability presented to you abode this would possibly not impact any kit you utilize yet could make a kettle sound distinct because it could take an prolonged or shorter time to realize boiling element as for the water scale is barely left whilst the water around the element is boiling (producing bubbles of air ) so leaving the water in will make no difference to the point of scale