Analytical chemistry 2, Lecture4 (the indicators)

Front

What color does Methyl Orange turn in acidic media?

Back

Red

Front

What type of indicators are weak organic acids or bases with high molecular weight that change color according to pH?

Back

Color indicator

Front

How is the pH range of an indicator calculated?

Back

pH = pKIn + log [basic color] / [acidic color]

Front

What are the functional groups responsible for the color absorption of the indicator?

Back

Chromophore

Front

What color does phenolphthalein turn in acidic media?

Back

Colorless

Front

What is the role of an auxochrome in indicators?

Back

It modifies the color of the chromophore and enhances color intensity.

Front

Define 'chromophore'.

Back

A chromophore is a part of a molecule responsible for its color, typically due to the presence of conjugated double bonds.

Front

What is the significance of pKIn in indicator chemistry?

Back

pKIn is the negative logarithm of the acid dissociation constant (Ka) of the indicator, indicating its strength as an acid.

Front

Explain the term 'color change range' in the context of indicators.

Back

The color change range is the pH range over which an indicator changes color, indicating the transition from acidic to basic.

Front

What is a fluorescent indicator?

Back

A fluorescent indicator is a compound that emits light upon excitation, often used to detect pH changes.