Which of the following statements is not correct?
A Brønsted-Lowry base is a proton acceptor
Ammonia can act as a Brønsted-Lowry base and Lewis base
A Lewis acid is an electron pair acceptor
A hydroxide ion can only act as a Lewis base
Which of the following statements are correct for a titration between 0.10 mol dm-3 propanoic acid and 0.10 mol dm-3 potassium hydroxide?
The equivalence point will be at pH 7
The salt formed will hydrolyse to form an acidic salt
The salt formed will be CH3COOK
At half equivalence point [CH3CH2COOH (aq)] = [CH3CH2COO- (aq)]
Which of the following statements about indicators are correct?
- The pKa of the indicator is the midpoint of the pH range
- The colour of the indicator depends upon the pH of the solution
- At the end point of a titration [HIn] = [In-]
Which statement about buffer solutions is not correct?
A buffer resists small changes in pH
A buffer can be formed from sodium hydroxide and an excess of ethanoic acid
The pH during a titration between a strong acid and weak base changes slowly in the buffer region
When a strong acid is added to a buffer, hydrogen ions react with salt ions
The pH range of four different indicators are:
|
Indicator
|
pKa
|
|
Methyl orange
|
3.7
|
|
Phenolphthalein
|
9.6
|
|
Phenol red
|
7.9
|
|
Bromothymol blue
|
7.0
|
Which indicator would be suitable for a titration involving hydrochloric acid and ammonia?
