Question

The molarity of an aqueous solution of hydrochloric acid, , is determined by titration with a M barium hydroxide, , solution. If 31.2 mL of barium hydroxide are required to neutralize 15.4 mL of the acid, what is the molarity of the hydrochloric acid solution?

Answer 1

Answer:

See explanation.

Explanation:

Hello there!

In this case, for this titration problem, we first need to set up the undergoing chemical equation between barium chloride and hydrochloric acid:

$2HCl+Ba(OH)_2\rightarrow BaCl_2+2H_2O$

Which occurs in a 2:1 mole ratio of acid to base and thus, we can write the following:

$2n_{base}=n_{acid}$

Which can be written in molarities and volumes:

$2M_{base}V_{base}=M_{acid}V_{acid}$

And we solve for the molarity of the acid:

$M_{acid}=\frac{2M_{base}V_{base}}{V_{acid}}$

Unfortunately, the molarity of the base was not given:

"The molarity of an aqueous solution of hydrochloric acid, , is determined by titration with a M barium hydroxide, , solution. If 31.2 mL of barium hydroxide are required to neutralize 15.4 mL of the acid, what is the molarity of the hydrochloric acid solution?"

Yet we can assume an arbitrary value, say 1.0 M in order to show you the solution so that you can modify it according to your given value:

$M_{acid}=\frac{2(1.0M)(31.2mL)}{(15.4mL)}=4.05M$

So you just need to modify the (1.0 M) by the actually given molarity of the acid.

Regards!