Question

2.In a titration, 25.00 cm3 of a solution of hydrochloric acid reacted with 18.40 cm3 of sodium hydroxide solution of concentration 0.15 mol/dm3.

The equation which represents the reaction is:
HCl + NaOH -----> NaCl + H2O
Calculate the concentration of hydrochloric acid in mol/dm3

Answer 1

0.11mol/dm³

Step-by-step explanation:

The reaction expression is given as:

HCl + NaOH → NaCl + H₂O

Volume of acid = 25cm³ = 0.025dm³

Volume of base = 18.4cm³ = 0.0184dm³

Concentration of base = 0.15mol/dm³

Solution:

The concentration of hydrochloric acid = ?

To solve this problem, let us first find the number of moles of the base;

Number of moles = concentration x volume

Number of moles = 0.15mol/dm³ x 0.0184dm³ = 0.00276mol

From the balanced reaction equation;

1 mole of NaOH will combine with 1 mole of HCl

Therefore, 0.00276mol of the base will combine with 0.00276mol of HCl

So;

Concentration of acid =
`(number of moles )/(volume)` =
`( 0.00276)/(0.025)` = 0.11mol/dm³