Molarity vs. Normality: What's the Difference?
Edited by Janet White || By Harlon Moss || Updated on October 19, 2023
Molarity is the number of moles of solute per liter of solution; normality is the number of equivalents of solute per liter of solution.
Key Differences
Molarity is a term that represents the concentration of a solute in a solution, specifically the number of moles of solute per liter of solution. On the other hand, normality expresses the concentration of reactive species in a given solution, often quantified as the number of gram equivalents per liter.
In molarity, the solute's actual chemical nature matters. It focuses solely on the number of moles of the substance in solution. In contrast, normality considers the reactivity or chemical equivalence of the solute, emphasizing how many times a substance can participate in a reaction.
Molarity remains consistent across reactions, as it is solely determined by the number of moles of solute. However, normality can vary depending on the reaction in which the substance participates. A compound may have different normalities for different reactions.
Molarity is represented by the symbol "M" and has the formula M = moles of solute/volume of solution in liters. Normality, denoted by "N", is calculated as N = equivalents of solute/volume of solution in liters.
In summary, while both molarity and normality are measures of concentration, they differ in their reference points. Molarity refers to the total number of moles of a substance, whereas normality relates to the substance's reactivity or chemical equivalence.
ADVERTISEMENT
Comparison Chart
Definition
Moles of solute per liter of solution.
Equivalents of solute per liter.
Denoted By
M
N
Consistency
Consistent across reactions.
Varies depending on the reaction.
Focus
Solely on number of moles.
On reactivity or chemical equivalence.
Formula
M = moles of solute/volume in liters.
N = equivalents/volume in liters.
ADVERTISEMENT
Molarity and Normality Definitions
Molarity
Measure of the number of moles of a solute dissolved in a liter of solution.
To prepare a 0.5 M NaCl solution, you'd dissolve 0.5 moles of NaCl in one liter of water.
Normality
Measure of concentration defined as equivalents of solute per liter of solution.
A 1 N solution of H2SO4 means there's one gram-equivalent of H2SO4 per liter.
Molarity
Standard way of expressing concentration in chemistry.
Knowing the molarity helps chemists predict reactions and behaviors of solutions.
Normality
Represents the number of reactive units in a solution.
Normality takes into account how many hydrogen ions an acid can donate in a reaction.
Molarity
Ratio of the moles of solute to the total volume of solution in liters.
The molarity indicates how many moles of a substance are in a given volume of solution.
Normality
Can change depending on the substance's reaction under consideration.
H2SO4 has a normality of 2N when considering its reaction as an acid, as it can donate two H+ ions.
Molarity
Concentration expressed in moles of solute per liter of solution.
A 2 M solution of HCl means there are 2 moles of HCl in every liter of the solution.
Normality
Used in acid-base titrations to denote the reactive capability.
When titrating, one must match the normality of the acid and base to ensure complete reaction.
Molarity
Representation of solute quantity relative to the volume of solution.
The higher the molarity, the more concentrated the solution.
Normality
Equivalent concentration that considers the number of times a substance can react.
The normality gives insight into how reactive a particular solution is in a given reaction.
Molarity
Abbr. M The concentration of a solution expressed in moles of solute per liter of solution.
Normality
The state or fact of being normal; normalcy.
Molarity
(chemistry) the concentration of a substance in solution, expressed as the number of moles of solute per litre of solution
Molarity
Concentration measured by the number of moles of solute per liter of solvent
FAQs
Why is normality used in acid-base titrations?
Normality takes into account the reactivity, allowing for matching equivalent amounts of acid and base.
Is molarity affected by temperature?
Yes, because volume can change with temperature, and molarity depends on volume.
Can molarity and normality be the same for a solution?
Yes, for substances like hydrochloric acid (HCl), where 1 mole equals 1 equivalent, the molarity and normality are the same.
What is molarity?
Molarity is the concentration of a solution expressed as the number of moles of solute per liter of solution.
Does the value of normality change for different reactions?
Yes, because it depends on the number of equivalents reacting.
Is molarity dependent on the nature of the solute?
Yes, it's based on the number of moles of the specific solute.
Which is a broader term, molarity or normality?
Molarity, as it's used across all solutions, while normality is specific to reactions.
Is normality relevant to all solutions?
No, it's mainly used for solutions where reactivity or equivalents are a concern, like acid-base or redox reactions.
When is normality more useful than molarity?
In reactions where the reactivity or number of equivalents of the substance is significant.
How is molarity used in everyday life?
It helps in preparing solutions with desired concentrations, especially in labs and industries.
How is the formula for molarity derived?
Molarity (M) = moles of solute/volume of solution in liters.
Can the volume of the solvent affect molarity?
Yes, molarity is dependent on the total volume of the solution.
What's the significance of a 1N solution?
It has one equivalent of solute per liter of solution.
Does increasing the amount of solute always increase molarity?
Yes, if the volume remains constant.
How is normality different from molarity?
Normality is the number of equivalents of solute per liter of solution, while molarity is the number of moles of solute per liter.
How can you convert molarity to normality?
Multiply molarity by the number of equivalents per mole of the substance.
Why is normality not always an integer?
Because it depends on the number of equivalents, which can be fractional.
Can two solutions with different molarities have the same normality?
Yes, if the substances have different numbers of equivalents per mole.
Can normality be less than molarity?
Yes, in cases where one mole of solute has more than one equivalent.
Can the molarity of a solution exceed 1?
Yes, molarity can be any positive value depending on the concentration.
About Author
Written by
Harlon MossHarlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Janet WhiteJanet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
