Acids alkalis and titrations

What is litmus used for and how does it change in acidic or alkaline solutions?

Litmus turns red in acid and blue in alkali.

What is phenolphthalein used for?

It is colourless in acid and turns pink in alkali.

What is methyl orange used for?

Turns red in acid and yellow in alkali.

How does the pH scale classify solutions?

0-3: Strongly acidic, 4-6: Weakly acidic, 7: Neutral, 8-10: Weakly alkaline, 11-14: Strongly alkaline.

What is universal indicator used for?

To measure the approximate pH of a solution by showing a range of colours.

What ions do acids and alkalis produce in aqueous solution?

Acids release H+ (hydrogen ions); Alkalis release OH- (hydroxide ions).

What happens when an alkali reacts with an acid?

The alkali neutralises the acid, forming a salt and water.

How do you carry out an acid-alkali titration?

1. Use a pipette to add a fixed volume of alkali into a conical flask. 2. Add a few drops of indicator (usually phenolphthalein). 3. Fill a burette with acid. 4. Slowly add acid while swirling until colour changes. 5. Repeat and take concordant results to find the average.