Estimate the pH of the unknown solution by using the litmus paper. Litmus paper shows the approximate pH level of the solution. If the pH is less than seven, the solution is acidic so you need an alkaline known solution. If the pH is greater than seven, the solution is alkaline so you need an acidic known solution.
Determine which indicator to use based on the approximate pH of the solution. For example, if your unknown's solution pH was about 5.5, you would use the indicator methyl red.
Pour the unknown solution into the buret and record the volume.
Pour the known solution into the beaker and record the volume. Then add a few drops of the indicator solution to the beaker.
Slowly drip the unknown solution from the buret into the beaker. Stop when the color changes. The color changes depending on the indicator. For example, if you are using methyl red, when the color changes from yellow to red the reaction is complete.
Determine the amount of unknown solution that you dripped into the beaker by subtracting the amount of unknown solution remaining in the buret from the amount that was originally in the buret. For example, if you originally put 40 mL of unknown solution in and there were only 10 mL remaining, you used 30 mL.
Determine the molarity of the unknown solution by multiplying the molarity of the known solution times the volume of the known solution and then dividing by the volume of the unknown solution. For example, if you had 45 mL of a 1.2 M (molar) known solution and you used 30 mL of the unknown solution, you would multiply 45 mL times 1.2 M and divide by 30 mL to find the unknown solution's molarity is 1.8 M.