Question

During the titration of a weak acid and a strong base, you would expect the ph at the endpoint of titration to be ____.

a. less than 7
b. more than 7
c. 7
d. there is not enough information to determine what the ph would be.

Answer 1

Answer: The correct answer is Option b.

Explanation: pH is the measure of acidity of basicity of the solution. It is basically known as power of hydrogen ion concentration. pH is the negative logarithmic of hydrogen ion concentration.

Mathematically,

`pH=-\log[H^+]`

More the hydrogen ion concentration, low is the pH and more acidic is the solution and vice-versa.

pH scale is from 0 to 14.

Acidic solutions vary from pH 0 to 6.9

Basic solutions vary from pH 7.1 to 14.

Neutral solution has a pH of 7.

For the reaction of weak acid (near to 7) and strong base (far from 7), the final pH will be far from 7 or more than 7. Hence, the pH of final solution will be more than 7 and will be basic in nature.

Answer 2

Answer is: b. more than 7.

The endpoint is the point at which the indicator changes colour in a colourimetric titration and that is point when titration must stop.

For example, basic salt sodium acetate CH₃COONa is formed from the reaction between weak acid (in this example acetic acid CH₃COOH) and strong base (in this example sodium acetate NaOH).

Balanced chemical reaction of acetic acid and sodium hydroxide:

CH₃COOH(aq) + NaOH(aq) → CH₃COONa(aq) + H₂O(l).

Neutralization is is reaction in which an acid (in this example vinegar or acetic acid CH₃COOH) and a base react quantitatively with each other.