1molL

1 mol L−1, commonly written as 1 M or 1 molar, is a unit of concentration used in chemistry to denote the molarity of a solution. Molarity is defined as the number of moles of solute dissolved in one liter of solution. Therefore, a 1 molar solution contains exactly one mole of a substance (measured in moles) per liter of total solution volume.

The concept of molarity is widely utilized in scientific research, laboratory procedures, and industrial processes to quantify and prepare solutions with precise concentrations. It enables chemists to predict reactions, determine stoichiometry, and ensure reproducibility. One mole corresponds to approximately 6.022 × 10^23 particles ( Avogadro's number), which translates into the amount of substance containing that number of constituent entities such as atoms, molecules, or ions.

To prepare a 1 molar solution, the required amount of solute (for example, 58.44 grams of sodium chloride for a NaCl solution, given its molar mass) is dissolved in a volumetric flask and then diluted to the 1-liter mark with solvent, typically water. Molarity is temperature-dependent because volume can expand or contract with temperature changes.

While molarity is a convenient and common measure, it has limitations, especially in systems where temperature shifts occur or where the solution's volume changes during reactions. In such cases, alternative concentration measures like molality or normality may be employed.

Overall, 1 mol L−1 is a fundamental concentration unit in chemistry, facilitating standardized communication and precise experimentation across various scientific disciplines.