Molar Solution

Last Updated: December 4, 2018

Definition - What does Molar Solution mean?

A molar solution is an aqueous solution that contains 1 mole (gram-molecular weight) of solute in 1 liter of the solution. This is the method most frequently used by chemists to express concentration. Molar concentration (molarity) is not same as molar solution. Molarity is the number of moles of solute per liter of solution.

Corrosion can be evaluated in molar solutions. For example, mild steel corrosion in 1M hydrochloric acid solutions can be evaluated using weight loss and electrochemical techniques (potentiodynamic polarization curves and impedance spectroscopy).

Molar solution can be used in the field of electrochemistry and metal corrosion as concentration units.

Corrosionpedia explains Molar Solution

There are two common types of "standard solutions" in chemistry:

  • Molar solutions
  • Normal solutions

Both of these solutions are concentrations (or strengths) of a particular component (solute) that is dissolved in a solvent.

For example, the molecular weight of sodium chloride (NaCl) is 58.44, so one gram molecular weight (equal to 1 mole) is 58.44g. If we dissolve 58.44g of NaCl in a final volume of 1 liter, we have made a 1 molar NaCl solution.

The factors needed to calculate molar solutions are moles of solute and the mass of solvent in volume. A mole is the molecular weight (MW) expressed in grams (sometimes referred to as the gram molecular weight (gMW) of a chemical). Thus, 1 M = 1 gMW of solute per liter of solution.

Sometimes it may be more efficient to use molarity when calculating concentrations.

Making a standard molar solution from aqueous acids or bases is a bit more involved than making a standard molar solution from a solid chemical. This is because nearly all liquid acids, no matter how concentrated they are, are already diluted to some extent with water.

In corrosion determination, the corrosive medium can be measured in molar solution.

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