Question

Phenolphthalein gives _________ colour with lime water.

Answer 1

Lime water:

• Lime water is an aqueous solution of $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$.
• Since Lime water is a metallic hydroxide, which is basic in nature.
• The dissociation of Lime water can be represented as:

$\underset{\mathrm{Calcium}\mathrm{hydroxide}}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)}\to \underset{\mathrm{Calcium}\mathrm{ion}}{{\mathrm{Ca}}^{2+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydroxide}\mathrm{ion}}{2{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$

• When phenolphthalein is added to a basic solution it turns pink.

So, Phenolphthalein gives Pink color with lime water.