Limewater is alkaline in nature with a pH typically around 12.4.

The process of turning limewater milky is used to identify $CO_{2}$ gas in gas evolution experiments.

Calcium hydroxide is also known as slaked lime.

Excessive carbon dioxide can turn the milky solution clear again due to the formation of soluble calcium bicarbonate: $CaCO_{3} + H_{2}O + CO_{2} \rightarrow Ca(HCO_{3})_{2}$.

Simple and low-cost indicator for $CO_{2}$ detection.

Saturated solution has low solubility, requiring careful filtration.

Used in the sugar industry to refine raw sugar.

Used in laboratory experiments for gas analysis.

Option A (Carbonated water) contains carbonic acid ($H_{2}CO_{3}$), not calcium hydroxide.

Option B (Black water) is typically alkaline water containing trace minerals and humic/fulvic acids.

Option C (Hard water) is water containing high concentrations of dissolved minerals like $Ca^{2+}$ and $Mg^{2+}$ ions, specifically carbonates, bicarbonates, or sulfates.