Titration is a widely used method to determine the concentration of a solution. One of the most common applications of titration is to determine the assay content of sodium hydroxide, also known as caustic soda. In this blog, we will go through the step-by-step process of determining the assay content of sodium hydroxide using titration method.
Step 1: Preparation of standard acid solution
To determine the assay content of sodium hydroxide, we will need to use a standard acid solution as the titrant. The most commonly used acid for this purpose is hydrochloric acid (HCl). To prepare a standard acid solution, we will need to weigh out a known amount of hydrochloric acid and dissolve it in distilled water. The concentration of the acid solution should be known in advance, typically around 0.1 N or 0.1 M.
Step 2: Preparation of sodium hydroxide sample
To prepare the sodium hydroxide sample, we will need to weigh out a known amount of sodium hydroxide and dissolve it in distilled water. The concentration of the sample is not known and will be determined by the titration.
Step 3: Setting up the titration apparatus
To set up the titration apparatus, we will need a burette, a pipette, a beaker, and a pH meter. The burette will be used to measure the volume of acid solution that is added to the sample. The pipette will be used to measure the volume of sample that is added to the beaker. The pH meter will be used to measure the pH of the sample during the titration.
Step 4: Adding the sample to the beaker
Using the pipette, add the sodium hydroxide sample to the beaker. The volume of the sample should be noted.
Step 5: Adding the acid solution to the sample
Start the titration by adding the acid solution to the sample in the beaker. The volume of acid solution added should be recorded. As the acid solution is added, the pH of the sample will change.
Step 6: Determining the endpoint
The endpoint of the titration is reached when the pH of the sample reaches a certain value. The most common endpoint for this titration is pH 7. The endpoint can be determined using the pH meter or by using an indicator such as phenolphthalein. Once the endpoint is reached, the volume of acid solution added should be recorded.
Step 7: Calculating the assay content of sodium hydroxide
To calculate the assay content of sodium hydroxide, we will need to use the following equation:
Assay content of sodium hydroxide = (Volume of acid solution added x Concentration of acid solution) / Volume of sample
The result will be expressed as a percentage. The typical assay content of sodium hydroxide is around 50%.
In conclusion, determining the assay content of sodium hydroxide using titration method is a simple and effective way to measure the concentration of a solution. The process involves preparing a standard acid solution, preparing a sample of sodium hydroxide, setting up the titration apparatus, adding the sample and acid solution, determining the endpoint, and calculating the assay content. The whole process is time-efficient and easy to follow, making it an ideal method for determining the assay content of sodium hydroxide in various industrial and laboratory settings
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