how would you test a substance to see if it is an acid/

Question

australopithecus · Answer

Take the pH of the compound, if it is below 7 it is likely acidic.

You could add an indicator that changes colour upon the presence of a acidity i.e. phenolphthalein

You could react it with a base and analyze the reaction mixture for the presence of a salt

australopithecus · Answer

Likely the first option is the best.

australopithecus · Answer

use some litmus paper

jfraser · Answer

react it with a metal, collect the gas that is produced (if any). If it makes a lighted splint "pop", then the substance is an acid

anonymous · Answer

Use pH paper or a pH meter.This will tell you if it is an acid,alkali or a neutral substance. :)

anonymous · Answer

The only criteria for whether a substance is an acid is whether it chemically reacts with a base.  All the tests you've been given are essentially various ways of reacting it with bases, e.g. a reaction with water that reduces the amount of H+ present (raises the pH) is a reaction in which water plays the role of a base.  In JFraser's test, the reduced active metal plays the role of what's called a Lewis base.