How do you calculate equivalent weight of lactic acid?

Answer 1

First have a copy of the Periodic Table, showing atomic masses alongside you.

Next the name is 2-hydroxypropanoic acid. Its formula is CH3CH(OH)COOH

From the formula you will notice that there are :-

3 x carbon

6 x hydrogen

3 x oxygen.

Reading the periodic table

The Atomic Mass of carbon is '12' . So 3 x 12 = 36

The atomic mass of hydrogen is '1' . so 6 x 1 = 6

The atomic mass of oxygen is '16'. so 3 x 16 = 48

Adding

36 + 6 + 48 = 90 The relative molecular mass of lactic acis.

NB Equivalent weight is an old fashioned name for moles.

Hence moles = mass(g) / Mr

or

Equivalent weight = mass(g) /Mr

So 1 mole = 90g / 90 = 1

or

1 equivalent weight = 90 g/ 90 = 1

2 equivalednt weights = 180g / 90 = 2

et. seq.,

Answer 2

To calculate the equivalent weight of lactic acid, you need to consider the acid dissociation of lactic acid. Lactic acid has two acidic protons that can dissociate. The equivalent weight is calculated by dividing the molecular weight of lactic acid by the number of acidic protons it can donate in a reaction. For lactic acid, with a molecular weight of 90.08 g/mol and 2 acidic protons, the equivalent weight would be 45.04 g/eq.

Answer 3

The molar mass of lactic acid is 90,07948 g.