Question

What is the volume of a 0.5 mol/L NaOH solution required to completely react with 20 mL of a 2.0 mol/L HCl solution? What is the pH value of the produced solution? (Hint: Write and balance the chemical reaction between HCl and NaOH, and then use the stoichiometric relation (molar relation) between NaOH and HCl to calculate the minimum volume of NaOH solution.) Group of answer choices

Answer 1

Answer:

The volume of NaOH required is 80mL

pH of the resulting solution is 7 since reaction produces a normal salt

Explanation:

First, we generate a balanced equation for the reaction as shown below:

NaOH + HCl —> NaCl + H2O

From the equation,

nA = 1

nB = 1

From the question,

Ma = 2.0 mol/L

Va = 20 mL

Mb = 0.5 mol/L

Vb =?

MaVa / MbVb = nA /nB

2x20 / 0.5 x Vb = 1

0.5 x Vb = 2 x 20

Divide both side by 0.5

Vb = (2 x 20)/0.5

Vb = 80mL

The volume of NaOH required is 80mL

Since the reaction involves a strong acid and a strong base, a normal salt solution will be produced which is neutral to litmus paper. So since the salt solution is neutral to litmus paper then the pH of the resulting solution is 7