Question

What is the molarity of a sodium hydroxide solution if 9.0 mL of the solution is titrated to the end point with 10.0 mL of standard 0.20M hydrochloric acid

Answer 1

Moles of HCL

0.20mol were in 1000mL of solution

How many moles could be in 10.0mL of the solution

$=\dfrac{0,2mol x 10.0mL}{1000mL} =0.002mol$

Equation for the reaction

NaOH + HCl $\to$ NaCl + H₂O

Mole ratio of HCl:NaOH is 1:1

Moles of NaOH use is therefore;

$=\dfrac{1}{1}x0.002mol = 0.002mol$

Concentration of NaOH $= \dfrac{0.002molx1000ml}{9.0mL} = 0.222M$