Determining Acids And Bases Using Litmus Paper
Litmus papers can be used by anyone without any expertise knowledge. Strong acids like HCl, HNOCOOH partially dissociate and give fewer amounts of protons. This color change is relevant to the p H of the solution.They only have to know which color is relevant to acidic and basic p H value. An acid with p H 1 is said to be very strong, and as the p H value increases, acidity is decreased. As the basicity increases, p H value will also increase and strong bases will have p H value 14. Sometimes the colors are not so contrasting, so it is bit difficult to determine the p H range.
In this mixture, there are about 10- 15 types of dyes.
Fill two clean cups halfway with distilled water; mix a gram or two of table salt into one.
Tear two inch-long strips of alkacid litmus paper and dip them into the cups, using one strip per cup.
• Litmus papers give only two colors, either red or blue based on the p H of the solution.
You probably think of acid as a dangerous substance. Generally, the p H value of acids ranges from zero to six. Bases also dissociate in the water like acids, but instead of producing H they produce OH- i.e. Alkalis become less alkaline when mixed with an acid. Some examples are caustic soda or sodium hydroxide, calcium hydroxide or limewater, borax.