Coursework 2 - Acids + definitions

Question 1

Why is phenolphthalein unsuitable for comparing strengths of acids?

Answer 1

It is colourless in acids, all acids will show up the same

Question 2

How does strength of acid affect rate of reaction?

Answer 2

Stronger acid = faster rate of reaction as more hydrogen ions are dissociated –> higher conc. so more frequent collisions

Question 3

How does the titre of acid-base titration change as strength of acid is varied?

Answer 3

Titre will be the same if all the acids are monobasic (or the same -basic) as the mole ratio will be constant so number of moles of acid will be the same

Question 4

pH for a strong acid

Answer 4

[H+] = [HA]

Question 5

pH of weak acid

Answer 5

[H+] = Square root ( Ka x [HA])

Question 6

What is the equivalence point?

Answer 6

The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution

Question 7

What is the end point?

Answer 7

The point in a titration at which there are equal concentrations of the weak acid and conjugate base forms of the indicator

Question 8

What is an acid - base pair?

Answer 8

A pair of two species that transform into each other by gain or loss of a proton