Question

A group of students is comparing the graphs of strong acid-strong base and weak acid-strong base titration curves, where the base is the titrant. Which statement inaccurately describes a difference between the two curves?

A. The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve.

B. At the equivalence points, the pH of the weak acid-strong base is greater than the pH of the strong acid-strong base.

C. At the half-equivalence points, the pH of the weak acid-strong base is greater than the pH of the strong acid- strong base.

D. The steep-rise interval in the weak acid-strong base curve is more pronounced than in the strong acid-strong base curve.


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Answer 1

The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve. Hence, option A is correct.

What is a weak acid?

Weak acids are acids that don't completely dissociate in solution.

A weak acid is an acetic acid. It has a of 1.8⋅$10^{-5}$. Calculate how much it will dissociate in water. Since acetic acid is a weak acid so large part will not dissociate completely.

$k_a=\frac{[CH_3COO^-]H^+]}{[CH_3COOH]}$

B is not true, it shows the titration curve for weak/strong acid titrated with a strong base. When choosing an indicator for colourimetric titration select one so that the pH jump at the equivalence point contains the interval p±1. Phenolphthalein has a p≈9, so to decide if it is a suitable indicator check if the pH jumps from 8 to 10 at the equivalence point.

C is not true either because of the very slow reaction.

Learn more about weak acid here:

https://brainly.com/question/12811944

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