reddit mcat In a titration, 27.4 mL of a 0.0154 M solution of Ba(OH)2 is needed to neutralize 20.0 mL of HCl. What was the concentration of the acid solution

0.422 M

Explanation:

Equation of the reaction,

2HCl(aq) + Ba(OH)₂(aq) ⇒ BaCl₂(aq)+2H₂O(l)

From the recation above,

2 moles of HCl is needed to neutralize 1 mole of Ba(OH)₂.

Using,

C'V'/CV = a/b Equation 1

Where C' = concentration of acid, C = concentration of base, V' = volume of acid, V = volume of base, a = number of moles of acid, b = number of moles of base.

make C' the subject of the equation.

C' = aCV/bV' Equation 2

a = 2 mole, b = 1 mole, C = 0.0154 M, V = 27.4 mL, V' = 20 mL

Substitute into equation 2

C' = (2×0.0154×27.4)/(1×20)

C' = 0.422 M.

Hence the concentration of acid is 0.422 M