What is the difference between a primary and a secondary standard?
What is the difference between a primary and a secondary standard?
To put it simply, a primary standard is a factual universal measurement while a secondary standard is a device directly calibrated previously by the primary standard.
What is primary and secondary standard give example?
Primary and Secondary Standards A primary standard is a reagent that we can use to dispense an accurately known amount of analyte. For example, a 0.1250-g sample of K2Cr2O7 contains 4.249×10−4 moles of K2Cr2O7. The concentration of a secondary standard is determined relative to a primary standard.
What is the difference between primary standard and standard solutions?
In analytical chemistry, a standard solution is a solution containing a precisely known concentration of an element or a substance. A primary standard is a reagent that is extremely pure, stable, has no waters of hydration, and has high molecular weight.
What is primary standard solution example?
Potassium hydrogen phthalate (usually called KHP) for standardisation of aqueous base and perchloric acid in acetic acid solutions. Sodium carbonate for standardisation of aqueous acids: hydrochloric, sulfuric acid and nitric acid solutions (but not acetic acid)
What are the examples of secondary standard solution?
Example: The foundation Sodium hydroxide (NaOH) is an example of a secondary standard. Commercially available NaOH contains impurities of Sodium chloride (NaCl), Sodium carbonate (Na2CO3), and Sodium sulfate (Na2SO4), and eagerly absorbs water (H2O) from the atmosphere.
How do you prepare a secondary standard solution?
A standard solution can be prepared by weighing method in the following way. (a) The mass of solute needed is calculated and weighed. (b) The solute is dissolved in some distilled water in a beaker. (c) The solution is transferred into a volumetric flask.
Is HCl a secondary standard?
A HCl solution is used as it can be prepared accurately and is quite stable. Because of this stability it is called a secondary standard. Even more accurate and stable standards are called primary standards.
Why is KMnO4 a secondary standard solution?
KMnO4 is not used as primary standard because it is difficult to obtain the pure state of KMnO4 as it is not free from MnO2. Also, the colour is so intense that it acts as its own indicator.
What is a secondary standard solution?
A secondary standard solution is a solution that is made specifically for a certain analysis. A secondary standard is a substance whose active agent contents have been found by comparison against a primary standard. This means it is usually standardized against a primary standard.
Why is HCl a secondary standard?
HCl Secondary Standard. A HCl solution is used as it can be prepared accurately and is quite stable. Because of this stability it is called a secondary standard. Even more accurate and stable standards are called primary standards.
Is NaOH a secondary standard?
Note: NaOH is secondary standard because NaOH contains impurities of NaCl, Na2SO4 etc. It absorbs water from the atmosphere and determines the concentration of NaOH in a solution, which is titrated against a primary standard weak acid.