How to find which compound is acid or basic. I need only a understanding or a basic tip or suggestin how to find whether a compound is an acid or base

Acids taste sour.They turns red litmus to blue where as base taste is bitter and it is slippery in nature.Bases turns blue litmus to red.

 To find if a compound is acidic just see if there is a presense of H⁺ ion in the compound e.g. HCl - it has a H⁺ ion . 

 To find if a compound is basic just see if there is a presense of OH^- ions in the compound e.g. NaOH - it has OH^- ion . 

Acoording To Arrhenius Theory

Base:-

an Arrhenius base is a substance that dissociates in water to form hydroxide (OH⁻) ions; that is, a base increases the concentration of OH⁻ ions in an aqueous solution.

Acid:-

an Arrhenius acid is a substance that dissociates in water to form hydrogen ions (H⁺);   that is, an acid increases the concentration of H⁺ ions in an aqueous solution

• an Arrhenius acid is a substance that dissociates in water to form hydrogen ions (H⁺);^[6] that is, an acid increases the concentration of H⁺ ions in an aqueous solution. This protonation of water yields hydronium (H₃O⁺);^[9] in modern times, the use of H⁺ is regarded as a shorthand for H₃O⁺, because it is now known that a bare proton (H⁺) does not exist as a free species in aqueous solution.^[10]
• an Arrhenius base is a substance that dissociates in water to form hydroxide (OH⁻) ions; that is, a base increases the concentration of OH⁻ ions in an aqueous solution.

 We can find a compound  is  acid or base by using litmus test.

Acides turnes red litmus to blue colour, in case of base it turnes blue  litmus to red.(or)

 According to arrhenius priniciple Acid will give H+ ions in aqueous (water) solution.where as Bases

will gives OH- ions.