Acids And Alkali Flashcards
How can you measure how acidic or alkaline a substance is?
The pH of a substance.
What is the range on the pH scale?
0-14.
What is an acid?
Anything that forms a solution with a pH of less than 7 and H+ ions in aqueous solutions.
What is an alkali?
Anything that forms a solution with a pH greater than 7 and produce OH- ions in aqueous solutions. They can also be bases which are soluble in water.
What is a neutral substance?
Substances that are neither acidic nor alkaline and have a pH of exactly 7. E.g pure water.
What is a base?
Chemicals that can neutralise an acid producing a salt and water. They are usually metaloxides or metal hydroxides.
How can you test the pH of a solution?
1) Universal indicator.
Changes colour depending whether a substance is an acid, alkaline or is neutral.
2) pH probe.
Determines pH electronically.
What are the colours on the universal indicator?
Goes in order of the rainbow starts with red for really acidic solutions, green for neutral solutions and purple for really alkaline solutions.
What is a neutralisation reaction?
When an acid and alkali react to form a salt and water.
What is the general equation for neutralisation reactions?
Acid + alkali —> salt + water
What is the neutralisation equation in terms of H+ and OH- ions?
H+ + OH- —> H2O
