How do I find the molarity (M) of a solution that contains 0.03 mole of HCl in 10.0L solution?

Question

Thanks.

Answer 1

Molarity is defined as moles/liter

The easiest way to "do" molarity is to set up a cross multiplication. Your example is way easy to see (just divide by 10) , but they're not always this easy.

0.03mole of HCL/ 10.0L = Xmole/1L

Cross multiply and you get: .03mol x 1L = .03mol

.03mol divided by 10.0 L = 0.003mol/Liter

Molarity (M) is defined as mol/Liter, so, change units from mol/L to M

Therefore, the molarity is 0.003M HCL or 3mM


Sometimes math scares people. Think of cross multiplying in words if you have trouble. Doing concentrations is like setting up an analogy.

Say something like this in your head:

"Zero point zero three moles in ten liters is the same as X moles in one liter." then go. "OK, 0.03 over 10 is the same as X over one. To solve for X, you multiply diagonally (there's only two numbers on the diagonal) and divide by the number that's left over.

Answer 2

Molarity is defined as the total number of moles solute per liter of solution.

So, the molarity of the HCl solution is 0.33Molar.

Answer 3

0.03mole in 10L; =0.003mole by liter
As HCl is a strong acid it is cmpletely disociated and the concentrations of [H+] is 0.003

pH = log 1/[H+]= log 1/0.003=-log 0.003=2.523