Why is sugar added when running the standard titration for the percent of available lime (CaO%) in quicklime?
The reason that sugar is added to the sample of quicklime after it has been added to water, is to increase the solubility of calcium hydroxide that was formed from the reaction of water and quicklime. This allows the lab technician to titrate quickly and is the reason the test is referred to as the Rapid Sugar Test for Available Lime. The solubility of calcium hydroxide in water is quite low, with a range of 0.185 grams per 100 grams saturated solution at 0o C to 0.071 grams at 100o C. (Note that the solubility decreases with an increase in temperature.) As the sample is stirred, a suspension of calcium hydroxide is maintained (milk of lime). As you titrate the calcium hydroxide in solution, more will dissolve. Since most of the calcium hydroxide exists as a solid in suspension, it cannot be titrated until it has dissolved (gone into solution.) The titration process itself involves a reaction of the acid with calcium hydroxide in solution and will consume lime, allowing more lime to go
- When I obtain a sample of quicklime from a truck or railcar for testing for the percent of available lime (CaO%) do I need to seal the container?
- What are the standard tests used to determine the percent of available lime (CaO%) of quicklime and how do they differ?
- Why is sugar added when running the standard titration for the percent of available lime (CaO%) in quicklime?