How do you know that an acid based reaction is completely neutralized?

When an acid and a base react with each other, a neutralization reaction occurs, forming a salt and water. The water forms from the combination of the H + ions from the acid and the OH - ions from the base. Strong acids and strong bases completely dissociate, so the reaction yields a solution with a neutral pH (pH = 7).

Explanation:

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.