An 80*mL volume of NaOH of 1.00*mol*L^-1 concentration was stoichiometrically equivalent to a 70*mL volume of HCl. What is [HCl]?

1 Answer
Dec 14, 2017

[HCl]=1.14*mol*L^-1, a tad more concentrated than is the base...

Explanation:

We write the stoichiometric equation that represents the reaction between hydrochloric acid, and sodium hydroxide....

NaOH(aq) + HCl(aq) rarr NaCl(aq) + H_2O(l)

And we do this to establish the 1:1 stoichiometry....and so then we use the definition of concentration....

"Concentration"="Moles of solute (mol)"/"Volume of solution (L)"

And so....

"moles of NaOH(aq)"=80.0*mLxx10^-3*L*mL^-1xx1.00*mol*L^-1=0.0800*mol

And there was an equivalent quantity of moles in a 70.0*mL volume of HCl(aq)...

[HCl(aq)]=(0.0800*mol)/(70.0*mLxx10^-3*L*mL^-1)=1.143*mol*L^-1