Acid-Base Indicators and Titration Concepts

The video tutorial by Ms. Cem explores acid-base indicators, focusing on their role as weak acids or bases with distinct colors in undissociated and dissociated forms. It explains how litmus paper changes color in acidic and alkaline solutions due to shifts in equilibrium. The concept of the end point, where an indicator changes color at a specific pH, is discussed, along with the relationship between pKa and pH. The video also covers how to choose appropriate indicators for titrations, using examples of weak acid-strong base and weak base-strong acid titrations.

What is the nature of acid-base indicators?

• Strong acids or bases

• Neutral compounds

• Weak acids or bases

• Salts

In an acidic solution, what color does litmus turn?

• Blue

• Green

• Yellow

• Red

What happens to the equilibrium in an alkaline solution?

• Becomes neutral

• Shifts to the right

• Remains unchanged

• Shifts to the left

When does an indicator change color?

• When pH is greater than 7

• When pH is neutral

• When pH is equal to its pKa

• When pH is less than 7

What is the pH range over which methyl orange changes color?

• 5.6 to 6.6

• 4.5 to 5.5

• 3.1 to 4.4

• 2.0 to 3.0

What is the pKa value of methyl orange?

• 6.7

• 5.7

• 4.7

• 3.7

Which indicator is suitable for a titration of a weak acid and a strong base?

• Methyl red

• Litmus

• Phenolphthalein

• Bromothymol blue

What is the pH at the equivalence point for a titration of a weak acid and a strong base?

• 7.0

• 9.5

• 3.5

• 5.0

Which indicator is suitable for a titration of a weak base and a strong acid?

• Phenolphthalein

• Methyl red

• Bromothymol blue

• Litmus

What is the pH at the equivalence point for a titration of a weak base and a strong acid?

• 3.0

• 9.5

• 7.0

• 5.0