1) Chemical test 2) Water 
Limewater is the common name for a saturated solution of calcium hydroxide. Calcium hydroxide, Ca(OH)2 is sparsely soluble in water (1.5 g/L at 25 °C.) Pure limewater is clear and colorless, with a slight earthy smell and an alkaline bitter taste of calcium hydroxide. The term lime refers to the alkaline mineral, and is unrelated to the acidic fr...
• (n.) Water impregnated with lime; esp., an artificial solution of lime for medicinal purposes.
Common name for a solution of calcium hydroxide.
Lime'wa`ter (-wa`tẽr) noun Water impregnated with lime; esp., an artificial solution of lime for medicinal purposes. 
[n] - solution of calcium hydroxide in water used as an antacid
noun solution of calcium hydroxide in water used as an antacid