Scoring Scheme: 3-3-2-1 Part II. You considered the properties of two acid-base indicators, phenolphthalein and methyl orange. Many indicators are weak acids in water and establish the equilibrium: HIn(aq)(Color 1) H2O(l) H3O (aq) In-(aq)(Color 2). Indicators change color depending on whether they are in a protonated (HIn) or unprotonated (In-) form. What is the equilibrium expression for the phenolphthalein indicator in water and what colors are the protonated and unprotonated forms of the indicator

Explanation:

Phenolphthalein is a protonated indicator and methyl orange is a basic indicator having hydroxyl ionisable part .

Phenolphthalein can be represented by the following formula

HPh  which ionizes in water as follows

       HPh        + H₂O      ⇄    H₃O⁺      +        Ph⁻

( colourless  )                    ( pink  )

In acidic solution it is in the form of protonated Hph form which is colourless

In basic medium , it ionises to give H₃O⁺ and unprotonated  Ph⁻ whose colour is pink .

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.