Ammonia is a weak base and establishes the following equilibrium in water: NH3(aq) + H2O(l) ---> NH4+ (aq) + OH-(aq). In Part III, the phenolphthalein indicator is used to monitor the equilibrium shifts of the ammonia/ammonium ion system. The phenolphthalein equilibrium established with water is Hph(aq)(colorless) + H2O(l) --> H3O+ (aq) + ph-(aq)(pink or red). You compared the color of the solutions in three test tubes that initially contained 3 mL of 0.1 M ammonium hydroxide and a few drops of phenolphthalein indicator. In a second test tube, you added 6 M NH4OH dropwise. Explain, in terms of the ammonia/ammonium ion equilibrium, why the phenolphthalein equilibrium shifted to the right.

Explanation:

phenolphthalein indicator is an acid - alkaline organic dye that changes color over a particular pH range depending on the medium. As such , asides phenolphthalein, methyl orange, Alzarian yellow are other indicators that are used during avid - base titration experiment.

In this case, phenolphthalein in an acidic medium is colorless while in basic medium is pink. Also phenolphthalein been a weak acid reacting with the hydroxide thereby reducing the concentration, this will have an effect on the equilibrium position by favoring the forward reaction i.e product formation. hence more products will be formed.

In the case of ammonium chloride, the addition of more ammonium ions results in an increase in the concentration of the products and as such, if more ammonium ions are removed, the equilibrium position will shift to favor the backward reaction i.e reactant formation.

organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance