What volume is required to prepare a 2.70 M HCl solution with 50.0 grams of HCl? What is the concentration of each ion?

Question

Please show work as well for a better understanding. :)

Answer 1

A concentration of 2.7M is really 2.7 mol/L of solvent. The key to this problem is determine how many moles you have of HCl, because you can use this and the concentration to determine volume.

HCl has a molar mass of:

H - 1.00784 g/mol

Cl - 35.453 g/mol

HCl- 36.46g/mol

Once you have the molar mass, you can use it to find tbe number of moles of HCl you are working with:

50g HCl * (1mol/36.46g) = 1.371mol

Then, you can use the original molarity to determine liters of solvent:

1.371mol / (2.7mol/L) = 0.507L of solvent

The concentration of each ion in this case is 2.7M, just like the overall concentration, because there is one H+ ion and one Cl- ion equivalent to every HCl. If the acid had been something like H3PO4, the concentration of the H+ ion would be 3x that of the acid overall.

Answer 2

To answer this question, we need to know the equation for Molarity, a unit of concentration:

Molarity (M) = moles of solute / L of solution

We are solving for L, the volume of solution. We are given the concentration of the solution and we can calculate the moles of solute from the grams that are given:

50.0 g HCl (1 mole of HCl / 36.46 g HCl) = 1.37 moles of HCl in 50.0 g of HCl

Now we can calculate the volume:

2.70 M = 1.37 moles / x L -----> x L = 1.37 moles / 2.70 M = 0.507 L of solution required to prepare a 2.70 M HCl solution with 50.0 g of HCl

Because the mole ratio of H+ and Cl- ions in HCl is 1:1, each ion has a concentration of 2.70 M in this solution.