Limewater

Lime water, also called Kalksinterwasser or just laden water, is the common name for an aqueous solution of calcium hydroxide. Lime water is alkaline and caustic.

Production

Slurried calcium hydroxide is sparingly soluble in water and filtered from the clear supernatant is obtained lime water.

Also by stirring of calcium oxide in water, a calcium hydroxide suspension from which is obtained by filtration of lime water:

In the preparation of slaked lime as a by- product lime. Here is the solution covered the deleted with water lime ( slaked lime ) during that matures in maturity basin to lime putty.

Use for analysis

With a clear lime water, one can detect carbon dioxide: When passing CO2 -containing air, a precipitate of calcium carbonate forms. For prolonged passage of carbon dioxide, the calcium carbonate dissolves with the formation of the calcium carbonate again.

According to the following reaction equation arises in the first step of the process initially carbonic acid ( H2CO3 ). Since these decays to other products immediately in water, it immediately reacts with the calcium hydroxide to calcium carbonate contained, which precipitates as a solid and causing the turbidity of the suspension:

Leaving lime water open for longer on the air, so the solution is useless because it absorbs CO2 from the atmosphere to form calcium carbonate.

This reaction takes place in a gas sample and in the detection of carbon dioxide Kalkwasserprobe.

Similar to lime water reacts with carbon dioxide baryta water.

Use in heritage conservation

Both with lime water as well as with baryta water was tried in the past to consolidate morbid natural stone or plaster: The solution was introduced into the capillary system in the hope that the precipitates stabilize the soil skeleton.

The effectiveness of such measures is scientifically refuted: If ever held a strength increase, so this is not due to a rearrangement of the existing mortar calcium hydroxide - This effect could be triggered in experiments by a simple impregnation with water.