Question

A student adds 4 mL of acetic acid to a test tube containing 4 mL of distilled water. He then shakes the test tube and leaves it to settle. After about 10 minutes he observes:(A) a layer of water over the layer of acetic acid(B) a layer of acetic acid over the layer of water(C) a precipitate settling at the bottom of the test tube(D) a clear colourless solution

Answer 1

Acetic Acid (CH3COOH) is highly soluble in Water (H2O). Reaction of Acetic acid and water is acid base reaction in which acid looses H+ ions and results in weak electroyte. 

Usually, solubility of acid into water depends on acid and water molecules. When the molecules of acid are dissolved in water, they disrupts the hydorgen bonding in water and acid molecules are able to form new H-bond with water molecules thus rendering it highly favorable reaction. 

CH3COOH + H2O --> CH3COO + H2O + H+

Thus at the end of your reaction time, you will see clear solution. 

Answer 2

The right answer is
(D) A clear colorless solution.
It is because reaction of acetic acid CH3COOH with water H2O is a simple neutralization reaction because water H2O acts as base and it will accept proton H+ from acetic acid CH3COOH. Reaction will be like this
CH3COOH + H2O ⇒ CH3COO- + H3O+
As it is a simple neutralization reaction so the solution will be colorless solution.