acids bases and alkalis

Bases are substances that react with acids and neutralise them. They are usually metal oxides, Many bases are insoluble - they do not dissolve in water. If a base does dissolve in water, we call it an alkali. Alkail is a base

Copper oxide is a base because it will react with acids and neutralise them and will not dissolve in water.

Sodium hydroxide is a base because it will react with acids and neutralise them. It’s also an alkali because it dissolves in water.

Neutralisation

• taste sour (don’t taste them!)… the word ‘acid’ comes from the Latin acere, which means ‘sour’ • acids change litmus (a blue vegetable dye) from blue to red • their aqueous (water) solutions conduct electric current (are electrolytes) • react with bases to form salts and water evolve hydrogen gas (H2) upon reaction with an active metal (such as alkali metals, alkaline earth metals, zinc, aluminum)

taste bitter (don't taste them!) feel slippery or soapy (don't arbitrarily touch them!) bases don't change the color of litmus; they can turn red (acidified) litmus back to blue their aqueous (water) solutions conduct and electric current (are electrolytes) react with acids to form salts and water

Hydrofluoric Acid - HF Hydrochloric Acid - HC

Sodium Hydroxide - NaOH Potassium Hydroxide - KOH Ammonium Hydroxide - NH4OH

exothermic …gives out heat

a universal indicator to establish level of acidity or alkalinity RED is acid Blue Alkali

acid positive hydrogen Ions H+ alkali Hydroxide negative Ions OH- H+(aq) + OH-(aq) = H2O (l) Water !!!