Ph Indicators Papers
pH Indicator Papers are sheets and strips of paper that have been dipped in an indicator solution or laced with a chemical compound that can help in determination of acidic/basic nature of a given solution and make an approximate value of their pH value. These papers come in a number of variations which depends upon the type of indicator solution they have been dipped in, and thus are suitable in getting a vague idea about pH value of a solution in a limited range. The reason for this limitation is that a particular indicator is susceptible to chemical change and exhibits smooth transformation at a particular pH range of the immediate surroundings.
1) The indicator papers can be of two types, with the simpler ones being capable of just undergoing a single color change to specify whether the solution is acidic or alkaline, like litmus paper strips.
2) The other kind of indicator papers show a wide range of shades on exposure to solutions of different pH, and change to a different color on coming in contact with each one of them.
3) These papers do not provide precise information about the pH of a solution, and are thus utilized only when rough knowledge of the aforesaid value is required.
4) Commonly used laboratory pH indicators have a transition range of pH values, and only within those values of their immediate surroundings do they show a smooth color transformation.