Acids and Alkalis revision

Hydrogen ions (H⁺)

The ions released by acids when they dissolve in water, making the solution acidic.

Acidic Solution

A solution characterized by a high concentration of hydrogen ions.

Neutralisation

The process of making an acid less acidic by adding a base.

Base

A substance that can neutralize acids.

Alkali

Soluble bases that release hydroxide ions (OH^-) in water, making the solution alkaline.

Hydroxide ions (OH^-)

The ions released by alkalis when they dissolve in water, contributing to the alkalinity of the solution.

pH Scale

A scale that measures how acidic or alkaline a solution is, ranging from 0 (very acidic) to 14 (very alkaline), with 7 being neutral.

Litmus

A natural dye indicator that changes color to red in acidic solutions and blue in alkaline solutions.

Universal Indicator

A mixture of indicators that shows different colors depending on the pH of a solution.

Neutral Solution

A solution that has a pH of 7, indicating it is neither acidic nor alkaline.

Phenolphthalein

An indicator that is colorless in acidic solutions and pink in alkaline solutions.

Bromothymol blue

An indicator that turns yellow in acidic solutions, green in neutral solutions, and blue in alkaline solutions.

Methyl orange

An indicator that turns red-orange in acidic solutions and yellow in neutral or alkaline solutions.

Hydrangeas

Plants that can act as natural indicators, producing blue flowers in acidic soil and pink flowers in alkaline soil.

Concentrated Hydrochloric Acid

An acid with a very low pH, making it very acidic (around pH 1).

Toothpaste

An alkaline substance with a pH of around 9.

Bleach

A very alkaline substance with a pH of around 13.

Salts and Water

The products formed when an acid reacts with a base in a neutralisation reaction.