A3.1 m solution contains 3.1 of solute dissolved in 1 of solution.
the m in 3.1 m refers to
the concentration of a 3.1 m solution may also be expressed as and would be expressed in

A 3.1 M solution contains 3.1 moles of solute dissolved in 1 liter of solution.

The M in 3.1 M refers to molarity. The concentration of a 3.1 M solution may also be expressed as normality and would be expressed in N

Explanation:

Molarity means, the moles of solute dissolved in 1 L of solution.

Normality means the equivalent weights per liter of solution.

How can you obtein the equivalent weights?

You have to know the molar mass of your compound and then divide between n, where n can be the valencia state of a compound, the electrons or protons transfer in reactions or, the number of H+ or OH- that a molecule transfer.

Equivalent weights = Molar mass / n