The method by which impurities and bran can be removed from the flour is

This method is used for separating bran from flour, sand from gravel, pearls of different sizes, etc. Winnowing:The process of separation of lighter particles from heavier particles; with the help of wind; is called winnowing. This method is also used for separating grains from husk.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds