Question

4.A 250 mL sample of HCl solution reacts with 2.5 g of Al according to the following reaction. Determine the concentrationof the HCI. Show your work for credit.6HCl(aq) + 2Al(s) -----> 2AICI, (aq) + 3H:(9)

Answer 1

In this question, we have the following reaction:

6 HCl + 2 Al -> 2 AlCl3 + 3 H2

We have:

250 mL of HCl

2.5 g of Al

And we want to find the molar concentration of HCl

One way of doing it is by finding the number of moles of HCl present in this solution, we can do that by using the number of moles of Al and after that, comparing the molar ratio of HCl and Al. To find the number of moles of Al, we will use its molar mass 27g/mol

27g = 1 mol

2.5g = x moles

x = 0.0926 moles of Al in 2.5 grams

Now by looking at the properly balanced reaction, we can see that the molar ratio between HCl and Al is 6:2, so if we have 0.0926 moles of Al, we will have:

6 HCl = 2 Al

x HCl = 0.0926 Al

x = 0.2778 moles of HCl

Now that we have the volume and the number of moles, we can find the molar concentration of HCl, using the Molarity formula:

M = number of moles/volume in liters

M = 0.2778/0.250

M = 1.11 is the molar concentration of HCl in this given solution