Question

Which of the following statements is NOT true? Select all that apply.

Group of answer choices

a. The concentration of H⁺ can be determined from the concentration of OH^- and the K_w.

b. An acid and its conjugate base differ only by one hydroxide ion

c. An acid with a K_a > 1 is considered a weak acid

d. The conjugate base of a strong acid will be a strong base

e. Strong acids are expected to completely ionize in solution

Answer 1

a) The concentration of H + ions can be determined from concentration of OH ^- and Kw.

ANSWER : TRUE

We have relation, [H⁺] [OH^-]= Kw

$\therefore$ [H⁺] = Kw / [OH^-]

If we know the [OH^-] then we can calculate [H⁺], hence given statement is true.

b) An acid and its conjugate base differ by only one OH ^-

ANSWER : FALSE

An acid and its conjugate base differ by only one H⁺.

Example : HCl $\rightleftharpoons$ Cl ^-

Cl ^- is a conjugate base of acid HCl. They differ by only one H⁺ ion. If we remove one H⁺ ion from HCl we get conjugate base , and if we add one H⁺ to Cl ^- we get conjugate acid HCl. Hence, given statement is false.

C) An acid with K a > 1 is considered weak acid.

ANSWER : FALSE

D) The conjugate base of strong acid will be strong base.

ANSWER : FALSE

The conjugate base of strong acid is always weak base.

E) Strong acids are expected to completely ionize in solution.

ANSWER : TRUE

Strong acids : Acids which completely ionize into the solution are called strong acids.

Weak acids : Acids which do not completely ionize into the solution are called weak acids.