The pH scale and neutralisation Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher

How can indicator colours be used to estimate pH?

Indicators change colour depending on pH, so their colour can be used to estimate pH.

What does the pH scale show about a solution?

How acidic or how alkaline the solution is.

What range does the pH scale run from?

0 to 14.

Which methods can be used to measure the pH of a solution?

• Approximately: universal indicator or a wide range indicator
• More directly: a pH probe

How do pH values classify a solution as acidic, neutral, or alkaline?

• Below 7: acidic
• 7: neutral
• Above 7: alkaline

What is neutralisation?

The reaction between an acid and an alkali.

What is the ionic equation for neutralisation, including state symbols?

$\ce{H+(aq) + OH-(aq) -> H2O(l)}$

In neutralisation, which reactant supplies the hydrogen ions and which supplies the hydroxide ions?

The acid supplies hydrogen ions; the alkali supplies hydroxide ions.

Which ions do acids produce in aqueous solution?

Hydrogen ions, $\ce{H+}$.

Which ions are present in alkaline aqueous solutions?

Hydroxide ions, $\ce{OH-}$.