pH Indicators

Which indicator would NOT be a good choice for the titration of a weak acid with a strong base?

• thymol blue

• phenolphthalein

• bromphenol blue

• thymolphthalein

Which indicator would NOT be a good choice for the titration of a weak base with a strong acid?

• bromcresol green

• phenolphthalein

• bromphenol blue

• methyl orange

According to the figure, when strong acid is added to water containing bromthymol blue indicator, the resulting solution will be

• blue

• green

• yellow

• Not enough info is given to answer this question.

According to the figure, when strong base is added to water containing bromthymol blue indicator, the resulting solution will be

• blue

• green

• yellow

• Not enough info is given to answer this question.

When strong base is added to water containing this indicator, the color shifts to

• blue because the OH^- reacts with H⁺, shifting the equilibrium to the right.

• blue because the OH^- reacts with HIn, shifting the equilibrium to the right.

• yellow because the OH^- reacts with H⁺, shifting the equilibrium to the left.

• yellow because the OH^- reacts with HIn, shifting the equilibrium to the left.

Which indicator would be a good choice for the titration of a strong acid with a strong base?

• thymol blue

• phenolphthalein

• bromthymol blue

• thymolphthalein

NH₃ (a weak base) is titrated with HCl using a methyl red indicator (red < 4.4 and yellow > 6.2). What color change should be observed at the endpoint?

• yellow to orange

• yellow to red

• orange to yellow

• red to yellow

An indicator should be chosen so that it has a distinct endpoint, or color change, at or near the _____________ of the titration.

• half-equivalence point

• buffering point

• starting point

• equivalence point

A particular titration results in a solution at the equivalence point with a pH of 6.00. Which of the following would be a good choice for an indicator?

• thymol blue

• phenolphthalein

• bromcresol purple

• thymolphthalein

An indicator has a K_a value of 7.9 x 10^-5. Which of these is the most likely identity of the indicator?

• thymol blue

• phenolphthalein

• bromphenol blue

• thymolphthalein