What is Acid-Base Titration?
An acid-base titration is a technique that is in use to experiment and acquire information about a solution containing an acid or base. As you are aware, there are hundreds of compounds, organic as well as inorganic. With the help of Titration, one can determine their acidic or basic properties. Acid is titrated with a base, and a base (alkali) is titrated with an acid. The use of an indicator decides the endpoint in Titration. Acid-base titrations are in use to calculate the amount of a known acidic or basic substance through acid-base reactions. The word Titration comes from the Latin word titulus, which means an inscription or a title. In the French language, the word title means rank. Hence, Titration implies the determinations of concentration or rank of a solution with respect to water with a pH of 7. A standard solution is added from an apparatus known as the burette. The process of adding a standard solution until the reaction is complete is called Titration. The substance to be determined is understood to be titrated.
What is Acid-Base Titration?
It is essential to note that all reactions in chemistry are not titrations. A reaction can get a reference as Titration only if it satisfies specific conditions. Here are a few conditions that help to determine whether a reaction is a titration:
The reaction has to be fast.
The change in free energy during the reaction must be large enough for the spontaneity of the reaction.
There must always be a way to decide the completion of the reaction.
(Image will be uploaded soon)
The Endpoint and the Equivalent Point in a Titration
The endpoint of a reaction is the stage that shows the completion of the reaction. The endpoint is detected by a physical change that is produced by the solution itself or by the addition of a reagent known as an indicator. The equivalent point is a stage where the amount of reagent added is exactly equivalent to the amount of the reacting substance in the titrated solution.
It is important to note that the endpoint and the equivalence point may not be identical. The endpoint is typically detected only after the addition of a slight excess amount of the titrant. If there is a difference between the endpoint and the equivalent point, then it amounts to an error in the experiment.
Acid-Base Titration Example
It is essential to measure accurately the volumes when doing titrations. The instrument in use for titration is called the burette. It is a type of liquid dispensing system that can indicate the volume of a liquid with precision.
Let us take an example.
Suppose, 25.66 ml or 0.02566 L of 0.1078 M HCL was used to titrate an unknown sample of NaOH. What mass of NaOH was in the sample?
We can calculate this by the number of moles of HCL reacted by:
mol HCL = (0.02566) (0.1078 M) = 0.002766 mol HCL
We also have a balanced chemical equation reaction between HCL and NaOH:
HCL + NaOH = NaCL + H2O
So, now we can construct a conversion factor to convert a number of moles of NaOH that reacted.
0.002766 mol HCL x 1 mol NaOH /1 mol HCL = 0.002766 mol NaOH
Now, we can convert this amount to mass using the molar mass of NaOH (40.00G/mol)
0.002766 mol HCL x 40.00 g NaOH / 1 mol HCL = 0.1106 g NaOH.
The mass of NaOH in the sample is 0.1106 g. This calculation is part of Titration.
Key Terms used in Acid-Base Titration
Titration - is the process where a solution of unknown strength adds to a specific volume of treated sample that contains an indicator.
A titrant - is a solution of known strength of concentration in use in titration.
A Titrant is any solution to which the titrant adds and which contains the ion that is being determined.
The Titration curve is a plotting of pH versus milliliters of titrant showing how pH changes versus milliliters of titrant during an acid-base titration.
The Equivalent point - is the point at which the reagent is added to react completely with a substance.
A Buffer solution - is a solution that resists changes in pH levels even when a strong acid or base is added or when it dilutes with water.
History of Acid-Base Titration
The acid-base reaction was initially postulated in the year 1754 by Guillaume-François Rouelle, who used the term "base" to describe a material that combines up with an acid to convert it to a solid form (in the form of a salt). The majority of bases are bitter in nature.
FAQs on Acid Base Titration
1. What are the Learning Objectives for Titration?
The learning objectives include finding reasons for the reaction of an acid with a base to make salt and water, common in any lab because so many compounds act as acids and bases. Another reason is that acid-base reactions are very common – hence they are widely used to determine the quantitative amount of one or the other. Now, the performance of a chemical reaction to quantitatively determine the precise amount of a reagent is known as the titration process. A Titration can be done with almost any chemical reaction for which we know the balanced chemical equation.
2. How do the indicators work in titration?
When we perform an acid-base titration reaction, an acid with a known concentration or a standard solution is gradually added to a base that has an unknown strength. The process can be vice-versa too. Now, a few drops of an indicator solution are added to a base. The indicator will give a signal with a change in the color of the solution. When the base is neutralized (when H+ = OH-) At this point, which is called the equivalent point or endpoint, the titration stops. When we know about the volumes of the acid and the base used, and the concentration of the standard solution, calculations let us determine the concentration of the other solution.
3. What are the key points to remember about titration?
As we already know Titration is a technique in chemistry that is used to find a concentration of an analyte (the titrant) which is unknown by reacting it with a known concentration and volume of a standardized solution (called the titrant). Titration is mainly used for acid-base reactions and redox reactions. The key points to remember about titration are:
The acid-base titration technique is a quantitative analysis for acids and bases; by this process, the acid or a base of known quantity or concentration neutralizes a base or acid of unknown concentration.
The progress in the titration process can be monitored easily with the help of visual indicators and also through pH electrodes, or both.
The reaction at which the titrant neutralizes the acid or base in the unknown analyte is known as the equivalence point. If the volume and concentration of the titrant are known at this equivalence point, then the concentration of a base or acid can be calculated in the solution that is unknown to us.
4. What is the step-by-step procedure to perform the acid-base titration?
Performing the acid-base titration is not that difficult but there are a few steps to remember which are the key points of this process:
Determining OH-: In the first step, we need to determine the OH- as we know that every mole of NaOH consists of at least one mole of OH-. Where OH- = 0.5M.
Determining the number of moles of OH-: The second step now is to find out how many numbers of OH- moles are present this could be found out by using the following formula:
Molarity = \[\frac{\text{No of moles}}{\text{volume}}\]
Number of moles = Molarity x Volume
Determining the number of moles of H+: The third important step to remember is to find out how many numbers of H+ are present because when the acid gets neutralized by the base the number of moles of H+ becomes equal to the number of moles of OH-.
Determining the concentration of HCl: The fourth and final step to remember is to find out the concentration of HCL as every mole of HCL produces a single mole of H+, which makes the number of moles of HCl equal to the number of moles of H+. The concentration of HCL can be found by a simple formula:
Molarity = \[\frac{\text{No of moles}}{\text{volume}}\]
5. How many types of titration methods are there other than acid-base titration?
There are mainly four types of titrations in chemistry that students need to memorize as titration is an important topic that has a high probability of being asked. Students can also find more content about this topic on Vedantu’s website in a simplified language which is very easy to learn and memorize.
The four types of titrations are as follows:
Acid-Base titration: Acid-Base titration is one of the four titration methods, which is a quantitative method to analyze and determine an acids or bases’ concentration in the solution by neutralizing them precisely with the help of a standard solution which could be of either base or acid of a known concentration.
Complexometric Titrations: When an undissociated complex is formed at an equivalence point there we can find the complexometric titrations.
Precipitation Titration: The precipitation titration is mainly based on the formation of an insoluble precipitate when two substances that are reacting are brought in contact are called precipitation titration.
Redox Titration: Redox titration is a chemical reaction that occurs with the transfer of electrons within the reacting ions of aqueous solutions. Redox titration is widely also known as an oxidation-reduction reaction. The titrations have been named after the reagents that are used in and are stated below:
Dichromate Titrations
Permanganate Titrations
Iodometric and Iodometric Titrations
