Acids and bases Flashcards
What is an acid?
- an acid is a substance that ionises in water to produce hydrogen ions
What is the definition of basicity of an acid?
- The basicity of an acid is defined as the number of moles of hydrogen ions produced when 1 mole of acid is dissolved in water
What are some examples of monobasic, dibasic and tribasic acids?
- hydrochloric acid (HCl) is monobasic
- its basicity is 1
- sulfuric acid (H₂SO₄) is dibasic
- its basicity is 2
- phosphoric acid (H3PO4) is tribasic
- its basicity is 3
What are the properties of acids?
- acids have a sour taste
- acids dissolve in water to form solutions that conduct electricity
- acids turn blue litmus red
What is formed when acids react with reactive metals?
- salt
- hydrogen gas
- e.g. magnesium + sulfuric acid → magnesium sulfate + hydrogen
Which metals do not react with acids?
- copper
- mercury
- silver
Why does lead not appear to react with dilute acids?
- lead appears not to react with dilute hydrochloric acid and dilute sulfuric acid
- the initial reaction between lead and dilute acid produces a layer of lead(ll) chloride or lead(ll) sulfate
- this layer is insoluble in water and forms a coat around the metal
- the coat prevents the metal from reacting with the acid
What is formed when a carbonate and an acid react?
- salt
- water
- carbon dioxide
- e.g. sodium carbonate + hydrochloric acid → sodium chloride + water + carbon dioxide
What is formed when acids react with bases (metal oxide/metal hydroxide)
- salt
- water
- e.g. zinc oxide + sulfuric acid → zinc sulfate + water
What is the role of water in the characteristic properties of acids?
- acids only display their properties when dissolved in water
- this is due to acids producing hydrogen ions when in water
- hydrogen ions give acids their acidic properties
- acids only behave as acids when acids ionise in water to produce hydrogen ions
What are the uses of sulfuric acid?
- to manufacture fertilizers such as ammonium sulfate
- to manufacture detergents
- for use as battery acid in cars
What is the use of hydrochloric acid?
- used to clean impurities such as rust or scale from metal and aluminium alloys
What is the use of ethanoic acid?
- used in vinegar to act as food preservative and flavor enhancers
What is the use of phosphoric acid?
- added to food and drinks to give them a sour taste
What is a base?
- a base is any metal oxide or hydroxide that reacts with an acid to form salt and water only
What are some common bases?
- sodium oxide (Na₂O)
- copper(ll) oxide (CuO)
- aluminium hydroxide (Al(OH)3)
- magnesium hydroxide (Mg(OH)2)
What is an alkali?
- an alkali is a base that is soluble in water that dissolves in it to form hydroxide ions
- e.g. sodium oxide
What are some common alkalis?
- sodium hydroxide
- potassium hydroxide
- calcium hydroxide
- barium hydroxide
- ammonium hydroxide
- remember i went to the SPA during Circuit Breaker to drink hydroxide