Question

which type of substances
used for indicate an acid or a base​

Answer 1

Answer:

An acid-base indicator is a weak acid or a weak base. The undissociated form of the indicator is a different color than the iogenic form of the indicator. An Indicator does not change color from pure acid to pure alkaline at specific hydrogen ion concentration, but rather, color change occurs over a range of hydrogen ion concentrations. This range is termed the color change interval. It is expressed as a pH range.

Answer 2

-->litmus paper test : blue litmus turn red litmus when immersed in acidic solution . red litmus to turn blue in basic\alkaline solution..

-->chemical test: certain chemical such as acidic and basic oxide react with acid and basic solution. respectively. however there are far too many reaction list..