Which piece of apparatus is used to add small measured volumes of one reactant to the other reactant during a titration?
Pipette
Burette
Measuring cylinder
Which piece of apparatus is used to accurately measure the volume of a reactant before transferring it to a conical flask?
Pipette
Burette
Measuring cylinder
If the initial reading in a titration is 0,50 cm3 and the final reading is 26,95 cm3, what is the titre (volume)?
26.95 cm3
27.45 cm3
26.45 cm3
12,0 cm3 of 1,00 mol.dm-3 base NaOH has been added to 5,0 cm3 of 2,00 mol.dm-3 HCl.
They react as: HCl + NaOH → NaCl + H2O. Which of the following statements is true?
The system is at the equivalence point
To reach the equivalence point, you need to add more NaCl
To reach the equivalence point, you need to add more NaOH
To reach the equivalence point, you need to add more HCl.
At which point in a titration does this graph represent?
The beginning, before the equivalence point
Before starting the titration, the set-up
The middle, right at the equivalence point
The end, once the equivalence point has been determined
You are titrating a base into a standard solution of acid and reach the equivalence point but the tap on the burette sticks, causing you to add a few extra drops of base into the acid. How will your calculated concentration of the base be affected? The calculated value will be ....
Higher than it really is
Lower than it really is
About the same as the actual value
Match the following titration set-ups with the corresponding titration curve:
Consider the following information regarding pH indicators:
At a low pH, a weak acid indicator is almost entirely in the HIn form, the colour of which predominates. As the pH increases - the intensity of the colour of HIn decreases and the equilibrium is pushed to the right. Therefore the intensity of the colour of In- increases. An indicator is most effective if the colour change is distinct and over a low pH range. For most indicators the range is within ±1 of its pH at its Ka value and at the point of changing colour [HIn] = [In-].
Consider an indicator that ionized as shown below for which its Ka = 1.0 x 10-4
Which of the responses are true statements? Select all that apply:
The predominant color in its acid range is yellow.
In the middle of its color change a solution containing the indicator will probably be orange
At pH = 7.00, a solution containing this indicator (and no other coloured species) will be red. (Hint: Write the equilibrium constant expression for the indicator.)
At pH = 7.00, most of the indicator is in the un-ionized form
The pH at which the indicator changes colour is pH = 4