- highly hydroscopic - reaction with water is highly exothermic - organic substances carbonize upon contact with H2SO4

- upon reaction with metal, toxic nitrogen oxides NO are formed - usage: fertilizers, explosives

Acid and Base reactions Flashcards by T Jihu

What is a super acid?

Super acids are stronger than sulfuric acids. (capable of protonating H2SO4)

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What is a magic acid?

Mixture of Bronsted/Lewis acids: Mix of SbF5/HSO3F (can protonate saturated hydrocarbons)

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What is paraffin?

saturated hydrocarbon (no electron pairs left) 
eg. methane

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Caution with HCl

conc. HCl releases highly currosive fume

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Caution with H2SO4

highly hydroscopic
reaction with water is highly exothermic
organic substances carbonize upon contact with H2SO4

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How is nitric acid produced?

2NO2 + H2O –> 2HNO3 + NO

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Features of HNO3

upon reaction with metal, toxic nitrogen oxides NO are formed
usage: fertilizers, explosives

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Properties of carbonic acid

H2CO3:

weak diprotic acid
forms water hardness from dissolved carbonates/sulfates (eg. Gypsum, lime)
when heated, insoluble sulfates/carbonates are formed

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How can water be softened?

dissolved salts must be removed through:

distillation
chelating
precipitation
ion exchange resin

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how can water be softened through chelating?

addition of ligands masking the cations

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How can water be softened through precipitation?

addition of substances to precipitate the cations

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What is the Haber Bosch production?

Production of ammonia (NH3)

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Characteristics of NH3

colourless gas,
toxic
pungent odour
highly water soluble
uses: fertilizer, explosives

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Caution of Hydroxides

very corrosive, damaging to eye

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What do hard acids preferably react with?

Hard bases

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What are characteristics of hard acids?

small, compact, non-polarizable, high charge

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Characteristics of soft acids/bases

large, more diffused distribution of electrons, polarizable

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Which one has higher lattice enthalpy, AgF or AgI?

AgI has high lattice enthalpy.

Ag+ is a soft acid, and I- is softer than F-

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For Ag X, does X have to be a hard or a soft base for it to be soluble?

Must be hard. Soft- Hard = polar = soluble

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What kind of combination of soft/hard acid base must be present for the compound to be soluble?

Soft-Hard = polar = polar

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How is the charge density of hard acids?

high charge density (metal ions have high positive charge and small ionic radius)
- d -orbitals do NOT engage in pi bonds

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How is the charge density of soft acids?

low charge density (low ionic charge and large ionic radius)

- d-orbitals are available for pi bonding

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Where are soft acids usually found?

2nd or 3rd row of transition metals with +1 / +2 charge and filled or almost filled

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Is H2O a hard or soft base?

hard

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is OH- a hard or soft base?

hard

Is NH3 a hard or a soft base?

hard

is BH3 a hard or a soft acid?

soft

Is NO2- a hard or soft base?

border

is SO3 a hard or soft acid?

hard

is NO3- a hard or soft base?

hard

is SO4 2- a hard or soft base?

hard

What are characteristics of hard bases?

Low charge, high electronegativity and small

Do strength of acid and bases have anything to HSAB?

Does HSAB or Acid Base Strength override a reaction?

HSAB

What is HOMO

highest occupied molecular orbital

what is LUMO?

Lowest UNoccupied molecular orbital

How is the interaction of LUMOs and HOMOs for Lewis acid and bases?

HOMO of base intereacts with LUMO of Lewis acid. MOs of adducts are lower in energy (stable)

What kind of orbitals are LUMOs and HOMOs

frontier orbitals

For ionic interaction to occur, must the difference in energy be large or small?

Large

Are Hard - Hard interactions , ionic or covalent?

ionic

Do hard acids have high or low LUMO?

High

Do soft acids have high or low LUMO?

low

Do hard bases have high or low HOMO?

low

Do soft bases have high or low HOMO

high

Are Soft-Soft interactions, ionic or covalent?

covalent (low energy difference between LUMO and HOMO)

General rule for period 2 elements?

Prefer double bonds

Do hard nucleophiles (OH-) react better with hard (H+) or soft electrophile (Br+)?

Hard-Hard combination

Are alkenes soft or hard nucleophiles?

soft

If an alkene is a soft nucleophile, does it have high or low HOMO?

high

Does a soft electrophile have a high or low LUMO?

low

What is activity defined as?

a(X) = f(X) · c(X)

what is f(x) (activity coefficient) equal to when the solution is dilute?

f(x) = 1

As concentration or ionic charge increases what happens to f(x)?

becomes 0

What are general requirements for titrations?

1. definite reaction 2. fast & quantitive 3. titrant must be stable 4. end point must be able to be determined

What are common titration methods?

1. acid-base titration 2. redox titration 3. complexation titration 4. precipitation titration

What is a bronsted Lowry acid?

Proton donor

Water can act as both an acid and a base. What is this property called?

amphotheric

Definition of concentration

amount of pure compound per volume

if Ka is very large what does it say about the strength of the acid?

the higher Ka, the stronger

How can the strength of an acid be determined?

- strength of H-X bond similar size = stronger bond (more overlap) = weaker acid - polarity of molecule more polar = readily ionized = stronger acid

If Y becomes more electronegative in Y - OH bond (oxyacids), does it become a stronger or weaker acid?

the more electronegative Y is, the weaker the OH bond = stronger acid

if more oxygen atoms are added, does it wekaen or strengthen the acid?

the more oxygen atoms, the stronger the acid - O atoms cause electron deficiency of central atom - OH bond becomes more polar

What is a Lewis acid?

Electron pair acceptor

As non metals act as Lewis acids, what kind of bonds do they form?

covalent

What kind of bond do basic oxides form in compound?

Ionic

What are cations usually in terms of Lewis acid base theory?

weak Lewis acids

What is the degree of protolysis?

ratio between dissociated and initial amount of an electrolyte α = [H+]/{HA]0

What is the equation for the degree of protolysis for weak acids?

α = square root (Ka/[HA]0)

What is the degree of titration?

= amount of titrant/ initial amount of analyte

name an indicator for a strong acid -strong base titration

litmus (pka = 6.5)

name an indicator for a weak base - strong acid titration

methyl orange (pka = 3.4)

name an indicator for a weak acid - strong base titration

phenophthalein (pKa = 9.4)

what is a buffer?

- can resist changes in pH when small amounts of acid or base is added. - consists of weak acid/base and its conjugate partner

What is a buffer capacity?

max. amount of acid/base that can be added before buffer cannot resist pH change - conc. buffer has a greater capacity

what is a displacement reaction?

volatile/insoluble weak acids/bases are removed by addition of strong base/acid (due to shift in equilibrium

Acid and Base reactions Flashcards

(75 cards)