Question

1 A solution of H2SO4 is labelled 40%, the density
of the solution is 1.3 gm/l. What is the
te concentration of the solution
in %​

Answer 1

Answer:

1 A solution of H2SO4 is labelled 40%, the density

of the solution is 1.3 gm/l. What is the

te concentration of the solution

in %​

Explanation:

The first thing to do here is pick a sample of this solution.

Since you're going to find its molarity, you can make the calculations easier by picking a  

1.00-L

sample. Keep in mind ,the answer will be the same regardless of the volume you pick.

So, use the density of the solution to determine how many grams you get in that respective volume

1.00

L

⋅

1000

mL

1

L

⋅

1.20 g

1

mL

=

1200 g

Now, you that the percent concentration by mass for this solution is  

40.0% HCl

. This means that you get  

40.0 g

of hydrochloric acid for every  

100.0 g

of solution.

The mass of hydrochloric acid you get in that sample will thus be

1200

g solution

⋅

40.0 g HCl

100

g solution

=

480 g HCl

Use hydrochloric acid's molar mass to determine how many moles you have in that many grams

480

g

⋅

1 mole HCl

36.46

g

=

13.17 moles HCl

The molarity of the solution will thus be - remember that we started with a  

1.00-L

sample

c

=

n

V

c

=

13.17 moles

1.00 L

=

13.2 M

→

rounded to three sig figs

SIDE NOTE This is very close to the maximum possible concentration for hydrochloric acid in aqueous solution. At this concentration, the solution is actually fuming at a significant evaporation rate.