02-27-2014, 05:57 PM
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Acids
Electrical conductivity
Any solution's ability to conduct electricity is defined by is charges ions in it. As a result, a strong acid will produce more charged ions than a weak one, and so it's solution will be a better electrical conductor than a weak acid. The same goes for strong/weak bases.
Acids in daily life
Concentrated acids: solution containing large amount of acid dissolved in water
Properties of acids
Common indicators:
Rule to make ionic equations:
2Na (s) + 2HCl (aq) → 2NaCl (aq) + H[sub]2[/sub] (g)
Its ionic equation is written as:
2Na (s) + 2H[sup]+ [/sup](aq) + 2Cl[sup]- [/sup](aq) → 2Na[sup]+ [/sup](aq) + 2Cl[sup]- [/sup](aq) + H[sub]2 [/sub](g)
Since 2 Cl[sup]- [/sup](aq) ions don’t change, they’re not involved in reaction.
As ionic equation is used to show changes in reactions, we omit Cl[sup]- [/sup](aq) ions.
So we’re left with:
2Na (s) + 2H[sup]+ [/sup](aq) → 2Na[sup]+ [/sup](aq) + H[sub]2 [/sub](g)Reaction between soluble ionic compounds and acids e.g. Reaction of sodium hydrogencarbonate with hydrochloric acid
NaHCO[sub]3 [/sub](aq) + HCl (aq) → NaCl (aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Its ionic equation is:
Na[sup]+ [/sup](aq) + H[sup]+ [/sup](aq) + CO[sub]3[/sub][sup]2- [/sup](aq) + H[sup]+ [/sup](aq) + Cl[sup]- [/sup](aq) → Na[sup]+ [/sup](aq) + Cl[sup]- [/sup](aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Since Na[sup]+ [/sup](aq) and Cl[sup]- [/sup](aq) ions don’t change, we omit them, leaving:
H[sup]+ [/sup](aq) + CO[sub]3[/sub][sup]2- [/sup](aq) + H[sup]+ [/sup](aq) → CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
CO[sub]3[/sub][sup]2- [/sup](aq) + 2H[sup]+ [/sup](aq) → CO
[sub]
[/sub](g) + H[sub]2[/sub]O (l)Reaction between insoluble ionic compounds and acids e.g. Reaction between iron(II) oxide and sulphuric acid
FeO (s) + H[sub]2[/sub]SO[sub]4 [/sub](aq) → FeSO
[sub]
[/sub](aq) + H[sub]2[/sub]O (g)
Its ionic equation is:
FeO(s) + 2H+ (aq) + SO[sub]4[/sub][sup]2- [/sup](aq) → Fe[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2- [/sup](aq) + H[sub]2[/sub]O (g)
Note: FeO is written in full as it is solid (although it is an ionic compound)
Since SO[sub]4[/sub][sup]2- [/sup](aq) ions don’t change, we omit SO[sub]4[/sub][sup]2- [/sup]ions, leaving:
FeO (s) + 2H[sup]+[/sup] (aq) → Fe[sup]2+ [/sup](aq) + H[sub]2[/sub]O (g)
E.g. Reaction between calcium carbonate and hydrochloric acid
CaCO[sub]3 [/sub](s) + 2HCl (aq) → CaCl[sub]2[/sub] (aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Its ionic equation is:
CaCO[sub]3[/sub] (s) + 2H[sup]+ [/sup](aq) + 2Cl[sup]-[/sup] (aq) → Ca[sup]2+[/sup] (aq) + 2Cl[sup]-[/sup] (aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Since 2 Cl[sup]-[/sup] (aq) ions don’t change, we omit Cl[sup]-[/sup] ions, leaving:
CaCO[sub]3 [/sub](s) + 2H[sup]+ [/sup](aq) → Ca[sup]2+ [/sup](aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)Reaction producing precipitate E.g. Reaction between calcium hydroxide and barium sulphate
Ca(OH)[sub]2[/sub] (aq) + BaSO[sub]4[/sub] (aq) → Ba(OH)[sub]2 [/sub](s) + CaSO[sub]4 [/sub](aq)
Its ionic equation is written as:
Ca[sup]2+[/sup] (aq) + 2OH[sup]-[/sup] (aq) + Ba[sup]2+[/sup] (aq) + SO[sub]4[/sub][sup]2- [/sup](aq) → Ba(OH)
[sub]
[/sub](s) + Ca[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2- [/sup](aq)
Since Ca[sup]2+ [/sup](aq) and SO[sub]4[/sub][sup]2- [/sup](aq) ions don’t change, we omit them, leaving:
Ba[sup]2+ [/sup](aq) + 2OH[sup]- [/sup](aq) → Ba(OH)[sub]2 [/sub](s)Displacement reactions E.g. Reactions between magnesium with zinc sulphate
Mg (s) + ZnSO[sub]4[/sub] (aq) → MgSO[sub]4[/sub] (aq) + Zn (s)
Its ionic equation is written as:
Mg (s) + Zn[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2- [/sup](aq) → Mg[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2-[/sup] (aq) + Zn (s)
Since SO[sub]4[/sub][sup]2-[/sup] (aq) ions don’t change, we omit them, leaving:
Mg (s) + Zn[sup]2+ [/sup](aq) → Mg[sup]2+ [/sup](aq) + Zn (s)Neutralization
[sub]
[/sub] + H[sub]2[/sub]O
H[sub]2[/sub]SO[sub]4[/sub] (aq) + NaOH (aq) --> Na[sub]2[/sub]SO
[sub]
[/sub](aq) + H[sub]2[/sub]O (g)
Ionic equation is:
H[sup]+ [/sup](aq) + OH[sup]-[/sup] (aq)→ H[sub]2[/sub]O (g)
Plants don’t grow well in acidic soil. Quicklime (calcium hydroxide) is added to neutralise the acidity of soil according to equation:
Acid (aq) + Ca(OH)[sub]2 [/sub](aq) --> Ca(acid anion) (aq) + H[sub]2[/sub]O (g)Reaction between Base and Ammonium Salts E.g. Reaction between NaOH and NH[sub]4[/sub]OH
NaOH (aq) + NH[sub]4[/sub]Cl (aq) --> NaCl (aq) + NH[sub]3[/sub] (g) + H[sub]2[/sub]O (g)
Ionic equation:
NH[sub]4[/sub][sup]+ [/sup](aq) + OH[sup]-[/sup](aq) → NH[sub]3[/sub] (g) + H[sub]2[/sub]O (g)Oxides[table][tr][td] Acidic oxide[/td][td]Oxides of non-metals, usually gases which reacts with water to produce acids, e.g. CO[sub]2[/sub], NO[sub]3[/sub], P[sub]4[/sub]O[sub]10[/sub], SO[sub]2[/sub][/td][/tr][tr][td] Basic oxide[/td][td]Oxides of metals, usually solid which reacts with water to produce alkalis, e.g. CaO, K[sub]2[/sub]O, BaO[/td][/tr][tr][td] Amphoteric oxide[/td][td]Oxides of transition metals, usually solid, which reacts with acids/alkalis to form salt and water, e.g. Al[sub]2[/sub]O[sub]3[/sub], FeO, PbO[/td][/tr][tr][td] Neutral oxide[/td][td]Oxides that don’t react with either acids/alkalis, hence do not form salts, e.g. H
[sub]
[/sub]O, CO, NO[/td][/tr][/table] Preparation of Salts[table][tr][td]Soluble [/td][td]Insoluble [/td][/tr][tr][td] All Nitrates[/td][td] -[/td][/tr][tr][td] All sulphates except -->[/td][td] BaSO[sub]4[/sub], CaSO[sub]4[/sub], PbSO[sub]4[/sub][/td][/tr][tr][td] All Chlorides except -->[/td][td] PbCl[sub]2 [/sub](soluble in hot water),
AgCl, HgCl[sub]2[/sub][/td][/tr][tr][td] Potassium, Sodium, Ammonium salts[/td][td] -[/td][/tr][tr][td] K[sub]2[/sub]CO[sub]3[/sub], Na[sub]2[/sub]CO[sub]3[/sub], (NH[sub]4[/sub])[sub]2[/sub]CO[sub]3[/sub][/td][td] All other carbonates[/td][/tr][tr][td] K[sub]2[/sub]O, Na[sub]2[/sub]O[/td][td] All other oxides[/td][/tr][/table]
Electrical conductivity
Any solution's ability to conduct electricity is defined by is charges ions in it. As a result, a strong acid will produce more charged ions than a weak one, and so it's solution will be a better electrical conductor than a weak acid. The same goes for strong/weak bases.
Acids in daily life
- Ethanoic acid – found in vinegar and tomato juice
- Citric acid – found in citrus foods like lemons, oranges and grapefruit
- Lactic acid – found in sour milk and yoghurt, and in muscle respiration
- Tartaric acid – found in grapes
- Tannic acid – found in tea and ant’s body
- Formic acid – found in bee stings
- Hydrochloric acid – found in stomach juices
- Hydrochloric acid (HCl)
- Sulphuric acid (H[sub]2[/sub]SO[sub]4[/sub])
- Nitric acid (HNO[sub]3[/sub])
Concentrated acids: solution containing large amount of acid dissolved in water
Properties of acids
- sour taste
- hazardous - irritants to skin, causing skin to redden and blister
- change the color of indicators - turn blue litmus red
- react with metals to produce hydrogen gas - gas is tested with a burning splint which burns with a 'pop' sound
- react with carbonates and hydrogencarbonates to produce carbon dioxide - to test this, the gas produced is bubbled into limewater which forms a white precipitate
- react with metal oxides and hydroxides - reach slowly with warm dilute acid to form salt and water
- sour taste
- Acids are stored in claypots, glass or plastic containers as sand, glass and plastic do not react with acids.
- If it is stored in metal container, metal would react with acids
- Sulphuric Acid
- Used in car batteries
- Manufacture of ammonium sulphate for fertilisers
- Manufacture of detergents, paints, dyes, artificial fibres & plastics
- Used in car batteries
- Hydrochloric acid
- can remove rust (iron(III) oxide) which dissolves in acids
- can remove rust (iron(III) oxide) which dissolves in acids
- Acids are used in preservation of foods (e.g. ethanoic acid)
- Acids are covalent compounds and do not behave as acids in the absence of water as water reacts with acids to produce H+ ions, responsible for its acidic properties
- e.g. Citric acid crystals doesn’t react with metals and doesn’t change colours of indicators; citric acid in water reacts with metals and change turns litmus red.
- e.g. Citric acid crystals doesn’t react with metals and doesn’t change colours of indicators; citric acid in water reacts with metals and change turns litmus red.
- Hydrogen gas is formed by acids as H+(aq) ions are present in acid solutions. This means when a solid/gas acid dissolved in water, they produce H+ ions in it
- Chemical eqation: HCl(s) ---(water)---> HCl (aq)
- Ionic Equation: HCl(s) ---(water)---> H[sup]+[/sup] (aq) + Cl[sup]-[/sup] (aq)
- Chemical eqation: HCl(s) ---(water)---> HCl (aq)
- However when dissolved in organic solutions, they don’t show acidic properties. When metals react with acids, only the hydrogen ions react with metals, e.g.:
- Chemical equation: 2Na(s) + 2HCl(aq) → 2NaCl(aq) + H[sub]2[/sub](g)
- Ionic equation: 2Na(s) + 2H[sup]+[/sup](aq) → 2Na+(aq) + H[sub]2[/sub](g)
- Chemical equation: 2Na(s) + 2HCl(aq) → 2NaCl(aq) + H[sub]2[/sub](g)
- Basicity of an acid is maximum number of H[sup]+[/sup] ions produced by a molecule of acid
- dibasic: can replace two hydrogen atoms
- tribasic: can replace three hydrogen atoms
- dibasic: can replace two hydrogen atoms
- Soft drink tablets contains solid acid (e.g. citric acid, C[sub]6[/sub]H[sub]8[/sub]O[sub]7[/sub]) & sodium bicarbonate
- When tablet is added to water, citric acid ionises and the H[sup]+[/sup] produced reacts with sodium bicarbonate to produce carbon dioxide gas, making them fizz
- Strong Acids - acid that completely ionises in water.
- Their reactions are irreversible.
- E.g. H[sub]2[/sub]SO[sub]4[/sub], HNO[sub]3[/sub], HCl
- H[sub]2[/sub]SO[sub]4[/sub] (aq) → 2H[sup]+ [/sup](aq) + SO[sub]4[/sub][sup]2-[/sup] (aq)
- In above H[sub]2[/sub]SO[sub]4[/sub] has completely been ionized in water, forming 3 kinds of particles:
- H+ ions
- SO[sub]4[/sub][sup]2-[/sup] ions
- H[sub]2[/sub]O molecules
- H+ ions
- In above H[sub]2[/sub]SO[sub]4[/sub] has completely been ionized in water, forming 3 kinds of particles:
- Strong acids react more vigorously with metals than weak acids – hydrogen gas bubbles are produced rapidly
- Their reactions are irreversible.
- Weak acids - acids that partially ionise in water.
- The remaining molecules remain unchanged as acids.
- Their reactions are reversible.
- E.g. CH[sub]3[/sub]COOH, H[sub]2[/sub]CO[sub]3[/sub], H[sub]3[/sub]PO[sub]4[/sub]
- H[sub]3[/sub]PO[sub]4[/sub] (aq) ⇌ 3H[sup]+ [/sup](aq) + PO[sub]4[/sub][sup]2- [/sup](aq)
- Weak acids react slowly with metals than strong acids – hydrogen gas bubbles are produced slowly.
- The remaining molecules remain unchanged as acids.
- Comparing 10 mol/dm[sup]3[/sup] and 0.1 mol/dm[sup]3[/sup] of hydrochloric acids and 10 mol/dm[sup]3[/sup] and 0.1 mol/dm[sup]3[/sup] of ethanoic acids
- 10 mol/dm[sup]3[/sup] of ethanoic acid solution is a concentrated solution of weak acid
- 0.1 mol/dm[sup]3[/sup] of ethanoic acid solution is a dilute solution of weak acid
- 10 mol/dm[sup]3[/sup] of hydrochloric acid solution is a concentrated solution of strong acid
- 0.1 mol/dm[sup]3[/sup] of hydrochloric acid solution is a dilute solution of strong acid
- 10 mol/dm[sup]3[/sup] of ethanoic acid solution is a concentrated solution of weak acid
- Bases are oxides or hydroxides of metals
- Alkalis are bases which are soluble in water
- All alkalis produces hydroxide ions (OH[sup]-[/sup]) when dissolved in water.
- Hydroxide ions give the properties of alkalis.
- They don’t behave as acids in absence of water.
- Alkalis are therefore substances that produce hydroxide ions, OH[sup]- [/sup](aq), in water.
- Sodium Hydroxide, NaOH
- Aqueous Ammonia, NH[sub]4[/sub]OH
- Calcium Hydroxide, Ca(OH)[sub]2[/sub]
- have a slippery feel
- hazardous
- Dilute alkalis are irritants
- Concentrated alkalis are corrosive and burn skin (caustic(i.e. burning) alkalis)
- change the colour of indicators: turn common indicator litmus – red litmus to blue
- react with acids
- The reaction is called neutralisation
- The reaction is called neutralisation
- react with ammonium compounds
- They react with heated solid ammonium compounds to produce ammonia gas
- (NH[sub]4[/sub])[sub]2[/sub]SO[sub]4[/sub] (s) + Ca(OH)[sub]2 [/sub](aq) → CaSO[sub]4[/sub] (aq) + 2NH[sub]3[/sub] (g) + 2H[sub]2[/sub]O (l)
- They react with heated solid ammonium compounds to produce ammonia gas
- react with solutions of metal ions
- Barium sulphate, BaSO[sub]4 [/sub](aq), contains Ba[sup]2+ [/sup](aq) ions
- Ca(OH)[sub]2 [/sub](aq) + BaSO[sub]4 [/sub](aq) → Ba(OH)[sub]2 [/sub](s) + CaSO[sub]4[/sub] (aq)
- The solid formed is precipitate – the reaction is called precipitate reaction
- Barium sulphate, BaSO[sub]4 [/sub](aq), contains Ba[sup]2+ [/sup](aq) ions
- Strong Alkalis: base that completely ionises in water to form OH[sup]- [/sup](aq) ions.
- Their reactions are irreversible.
- E.g. NaOH, KOH, Ca(OH)[sub]2[/sub]
- Ca(OH)[sub]2 [/sub](s) → Ca[sup]2+ [/sup](aq) + 2OH[sup]- [/sup](aq)
- Their reactions are irreversible.
- Weak Alkalis: base that partially ionise in water.
- The remaining molecules remain unchanged as base.
- Their reactions are reversible.
- E.g. NH[sub]3[/sub]
- NH[sub]3 [/sub](g) + H[sub]2[/sub]O (l) ⇌ NH[sub]4[/sub][sup]+ [/sup](aq) + OH[sup]- [/sup](aq)
- The remaining molecules remain unchanged as base.
- Alkalis neutralise acids in teeth (toothpaste) and stomach (indigestion)
- Soap and detergents contain weak alkalis to dissolve grease
- Floor and oven cleaners contain NaOH (strong alkalis)
- Ammonia (mild alkalis) is used in liquids to remove dirt and grease from glass
Common indicators:
- Litmus
- Methyl orange
- Phenolphtalein
- pH 7 is neutral – in pure water
- solutions of less than pH 7 are acidic.
- The solutions contain hydrogen ions.
- The lower the pH, the more acidic the solution is and more hydrogen ions it contains.
- The lower the pH, the more acidic the solution is and more hydrogen ions it contains.
- The solutions contain hydrogen ions.
- solutions of more than pH 7 are alkaline.
- The solution contains hydroxide ions.
- The higher the pH, the more alkaline the solution and more hydroxide ions it contains.
- The higher the pH, the more alkaline the solution and more hydroxide ions it contains.
- The solution contains hydroxide ions.
- Universal indicators
- It can be in paper or solution form.
- Universal paper can be dipped into a solution then pH found is matched with the colour chart.
- It gives approximate pH value.
- It can be in paper or solution form.
- pH meter
- A hand-held pH probe is dipped into solution and meter will show the pH digitally or by a scale.
- Measures pH water in lakes, water, and streams accurately
- A hand-held pH probe is dipped into solution and meter will show the pH digitally or by a scale.
- pH sensor and computer
- A probe is dipped into solution and will be sent to computer through interface used to measure pH of solution.
- The pH reading is displayed on computer screen.
- A probe is dipped into solution and will be sent to computer through interface used to measure pH of solution.
Rule to make ionic equations:
- Only formulae of ions that change is included; ions don’t change = omitted
- Only aqueous solutions are written as ions; liquids, solids and gases written in full
2Na (s) + 2HCl (aq) → 2NaCl (aq) + H[sub]2[/sub] (g)
Its ionic equation is written as:
2Na (s) + 2H[sup]+ [/sup](aq) + 2Cl[sup]- [/sup](aq) → 2Na[sup]+ [/sup](aq) + 2Cl[sup]- [/sup](aq) + H[sub]2 [/sub](g)
Since 2 Cl[sup]- [/sup](aq) ions don’t change, they’re not involved in reaction.
As ionic equation is used to show changes in reactions, we omit Cl[sup]- [/sup](aq) ions.
So we’re left with:
2Na (s) + 2H[sup]+ [/sup](aq) → 2Na[sup]+ [/sup](aq) + H[sub]2 [/sub](g)Reaction between soluble ionic compounds and acids e.g. Reaction of sodium hydrogencarbonate with hydrochloric acid
NaHCO[sub]3 [/sub](aq) + HCl (aq) → NaCl (aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Its ionic equation is:
Na[sup]+ [/sup](aq) + H[sup]+ [/sup](aq) + CO[sub]3[/sub][sup]2- [/sup](aq) + H[sup]+ [/sup](aq) + Cl[sup]- [/sup](aq) → Na[sup]+ [/sup](aq) + Cl[sup]- [/sup](aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Since Na[sup]+ [/sup](aq) and Cl[sup]- [/sup](aq) ions don’t change, we omit them, leaving:
H[sup]+ [/sup](aq) + CO[sub]3[/sub][sup]2- [/sup](aq) + H[sup]+ [/sup](aq) → CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
CO[sub]3[/sub][sup]2- [/sup](aq) + 2H[sup]+ [/sup](aq) → CO
[sub]
Code:
2
FeO (s) + H[sub]2[/sub]SO[sub]4 [/sub](aq) → FeSO
[sub]
Code:
4
Its ionic equation is:
FeO(s) + 2H+ (aq) + SO[sub]4[/sub][sup]2- [/sup](aq) → Fe[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2- [/sup](aq) + H[sub]2[/sub]O (g)
Note: FeO is written in full as it is solid (although it is an ionic compound)
Since SO[sub]4[/sub][sup]2- [/sup](aq) ions don’t change, we omit SO[sub]4[/sub][sup]2- [/sup]ions, leaving:
FeO (s) + 2H[sup]+[/sup] (aq) → Fe[sup]2+ [/sup](aq) + H[sub]2[/sub]O (g)
E.g. Reaction between calcium carbonate and hydrochloric acid
CaCO[sub]3 [/sub](s) + 2HCl (aq) → CaCl[sub]2[/sub] (aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Its ionic equation is:
CaCO[sub]3[/sub] (s) + 2H[sup]+ [/sup](aq) + 2Cl[sup]-[/sup] (aq) → Ca[sup]2+[/sup] (aq) + 2Cl[sup]-[/sup] (aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)
Since 2 Cl[sup]-[/sup] (aq) ions don’t change, we omit Cl[sup]-[/sup] ions, leaving:
CaCO[sub]3 [/sub](s) + 2H[sup]+ [/sup](aq) → Ca[sup]2+ [/sup](aq) + CO[sub]2 [/sub](g) + H[sub]2[/sub]O (l)Reaction producing precipitate E.g. Reaction between calcium hydroxide and barium sulphate
Ca(OH)[sub]2[/sub] (aq) + BaSO[sub]4[/sub] (aq) → Ba(OH)[sub]2 [/sub](s) + CaSO[sub]4 [/sub](aq)
Its ionic equation is written as:
Ca[sup]2+[/sup] (aq) + 2OH[sup]-[/sup] (aq) + Ba[sup]2+[/sup] (aq) + SO[sub]4[/sub][sup]2- [/sup](aq) → Ba(OH)
[sub]
Code:
2
Since Ca[sup]2+ [/sup](aq) and SO[sub]4[/sub][sup]2- [/sup](aq) ions don’t change, we omit them, leaving:
Ba[sup]2+ [/sup](aq) + 2OH[sup]- [/sup](aq) → Ba(OH)[sub]2 [/sub](s)Displacement reactions E.g. Reactions between magnesium with zinc sulphate
Mg (s) + ZnSO[sub]4[/sub] (aq) → MgSO[sub]4[/sub] (aq) + Zn (s)
Its ionic equation is written as:
Mg (s) + Zn[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2- [/sup](aq) → Mg[sup]2+ [/sup](aq) + SO[sub]4[/sub][sup]2-[/sup] (aq) + Zn (s)
Since SO[sub]4[/sub][sup]2-[/sup] (aq) ions don’t change, we omit them, leaving:
Mg (s) + Zn[sup]2+ [/sup](aq) → Mg[sup]2+ [/sup](aq) + Zn (s)Neutralization
- Neutralization is the reaction between acid and base to form salt and water only.
- From ionic equation, we know that the reaction only involves H[sup]+[/sup] ions from acids with OH[sup]-[/sup] ions from alkali to form water .
[sub]
Code:
4
H[sub]2[/sub]SO[sub]4[/sub] (aq) + NaOH (aq) --> Na[sub]2[/sub]SO
[sub]
Code:
4
Ionic equation is:
H[sup]+ [/sup](aq) + OH[sup]-[/sup] (aq)→ H[sub]2[/sub]O (g)
Plants don’t grow well in acidic soil. Quicklime (calcium hydroxide) is added to neutralise the acidity of soil according to equation:
Acid (aq) + Ca(OH)[sub]2 [/sub](aq) --> Ca(acid anion) (aq) + H[sub]2[/sub]O (g)Reaction between Base and Ammonium Salts E.g. Reaction between NaOH and NH[sub]4[/sub]OH
NaOH (aq) + NH[sub]4[/sub]Cl (aq) --> NaCl (aq) + NH[sub]3[/sub] (g) + H[sub]2[/sub]O (g)
Ionic equation:
NH[sub]4[/sub][sup]+ [/sup](aq) + OH[sup]-[/sup](aq) → NH[sub]3[/sub] (g) + H[sub]2[/sub]O (g)Oxides[table][tr][td] Acidic oxide[/td][td]Oxides of non-metals, usually gases which reacts with water to produce acids, e.g. CO[sub]2[/sub], NO[sub]3[/sub], P[sub]4[/sub]O[sub]10[/sub], SO[sub]2[/sub][/td][/tr][tr][td] Basic oxide[/td][td]Oxides of metals, usually solid which reacts with water to produce alkalis, e.g. CaO, K[sub]2[/sub]O, BaO[/td][/tr][tr][td] Amphoteric oxide[/td][td]Oxides of transition metals, usually solid, which reacts with acids/alkalis to form salt and water, e.g. Al[sub]2[/sub]O[sub]3[/sub], FeO, PbO[/td][/tr][tr][td] Neutral oxide[/td][td]Oxides that don’t react with either acids/alkalis, hence do not form salts, e.g. H
[sub]
Code:
2
AgCl, HgCl[sub]2[/sub][/td][/tr][tr][td] Potassium, Sodium, Ammonium salts[/td][td] -[/td][/tr][tr][td] K[sub]2[/sub]CO[sub]3[/sub], Na[sub]2[/sub]CO[sub]3[/sub], (NH[sub]4[/sub])[sub]2[/sub]CO[sub]3[/sub][/td][td] All other carbonates[/td][/tr][tr][td] K[sub]2[/sub]O, Na[sub]2[/sub]O[/td][td] All other oxides[/td][/tr][/table]