How do you know if a solution is acidic, basic, or neutral?

one way to tell is to use an indicator,which is a special type of organic compound that changes color as the ph of a solution changes. this is called a ph scale, in which the strength of an acid,or a base in a liquid solution is measured.the ph scale is a series of numbers from 0 to 14. the lower the ph number the greater the concentration of H+ ions. a neutral substance, such as pure water,has a ph of 7 and is neither an acid nor a base. any ph number over 7 indicates a base similarily,any ph value under 7 indicates an acid.