Difference Between Stock Solution and Standard Solution

The key difference between stock solution and standard solution is that stock solution is a highly concentrated solution, whereas standard solution is a solution having a precisely known concentration.

Stock solution and standard solution are related terms because standard solutions often come as stock solutions. This means, sometimes we can use these terms interchangeably. There are two types of standard solutions as primary standards and secondary standards. A stock solution can be either a primary or a secondary standard, or it can be some other chemical reagent as well.

1. Overview and Key Difference
2. What is a Stock Solution
3. What is a Standard Solution
4. Side by Side Comparison – Stock Solution vs Standard Solution in Tabular Form
5. Summary

What is a Stock Solution?

A stock solution is a highly concentrated solution. These solutions are very useful because we can dilute a portion from the stock solution to get a desired concentration. These stock solutions are important in saving preparation time of chemical reagents. Moreover, it helps us to conserve material. This means using a stock solution to get a low concentrated solution consumes only the portion from the stock and solvent that is needed for the dilution process. It is also important to reduce the storage space because we don’t need to prepare the solution using different reagents via sophisticated methods; we only need to dilute the stock solution. In addition, it improves the accuracy of experiments.

A stock solution is a large volume of a chemical reagent. It has a standardized concentration. For example, hydrochloric acid and sodium hydroxide are common stock solutions in laboratories. These are very important in preparing the solutions required for titrations.

What is a Standard Solution?

A standard solution is a concentrated solution having a precisely known concentration. In the preparation of a standard solution, we can use an accurately weighed solute and dissolve it in a suitable solvent to get a specific volume of the solution. There are two types as primary standard solutions and secondary standard solutions. A primary standard has sufficiently a precise concentration, and we don’t need to calibrate it using another chemical reagent. A secondary standard is a reagent that has been standardized using a primary standard. The major application of primary and secondary standards is to determine the concentration of an unknown reagent, mainly in titration processes.

These are some important properties of standard solutions:

The concentration is constant at all the time
Reacts rapidly with the analyte
Reaction proceeds to completion
Can describe the quantities using a balanced chemical equation
Can detect the equilibrium point, if any.

What is the Difference Between Stock Solution and Standard Solution?

We often use the terms stock solution and standard solution interchangeably. The key difference between stock solution and standard solution is that stock solution is a highly concentrated solution, whereas standard solution is a solution having a precisely known concentration. Moreover, a stock solution can be a large volume of a highly concentrate solute that can be any chemical reagent, but standard solution contains a certain chemical element or compound at highly precise concentration.

When considering their applications, stock solutions are important in saving preparation time of chemical reagents, to conserve material, to reduce the storage space, etc. while a standard solution is important in determining the unknown concentration of an analyte.

The below info-graphic summarizes the difference between stock solution and standard solution.

Summary – Stock Solution vs Standard Solution

Most of the times, we can use the terms stock solution and standard solution interchangeably. The key difference between stock solution and standard solution is that the stock solution is a highly concentrated solution, whereas standard solution is a solution having a precisely known concentration.

Reference:

1.“Stock Solution.” Wikipedia, Wikimedia Foundation, 1 Jan. 2019, Available here.
2.“Standard Solution.” Wikipedia, Wikimedia Foundation, 19 Oct. 2019, Available here.
3. Helmenstine, Anne Marie. “What Is a Primary Standard in Chemistry?” ThoughtCo, Oct. 5, 2019, Available here.