G. Reactivities of Inorganic Compounds Flashcards

(51 cards)

1
Q

Acid and bases properties

A

Acid - sour, blue to red litmus, corrode metals to produce hydrogen gas

Base - bitter, red to blue litmus, slippery

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2
Q

Differentiate the three definitions of acid and base

A
  1. Arrhenius
    → acid: produces H+ ions (H3O+)
    → base: produces OH- ions
  2. Bronsted-Lowry
    → acid: H+ donor
    → base: H+ acceptor
  3. Lewis
    → acid: electron pair acceptor
    → base: electron pair donor
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3
Q

Differentiate amphoteric and amphiprotic

A

Amphoteric - can act as base or acid
Amphiprotic - can both donate and accept a proton (Bronsted-Lowry)

NOTE: all amphiprotic substances are amphoteric, but not all amphoteric substances are amphiprotic

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4
Q

Factors that influence acidity

A

Charge, Atom, Resonance, Dipole Interaction, Orbitals

(CARDIO)

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5
Q

As charge became more ___, acidity increases (↓pH). Explain

A

As charge became more positive, acidity increases (↓pH)

OH- < H2O < H3O+

→ higher positive charge stabilizes the conjugate base
→ easier to release a proton

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6
Q

Arrange the following in order of increasing acidity. Explain

NH3, H2O, CH4, HF

A

CH4 < NH3 < H2O < HF

↑ acidity as ↑ EN across a period
→ EN atoms attract electron density more strongly
→ stabilizes the conjugate base

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7
Q

Arrange the following in order of increasing acidity. Explain

HF, HCl, HBr, HI

A

HF < HCl < HBr < HI

↑ acidity as ↑ size down a group
→ large atoms form weaker X-H bonds
→ easier to release H+ ions

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8
Q

Acidity increases with stability of ____ due to _____

A

↑ acidity ↑ stability of conjugate base due to resonance

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9
Q

Which is more acidic?

HOOCCH2CH2Br or HOOCCH2Br

A

HOOCCH2Br

↑ acidity as ↓ distance of EWG (Br)

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10
Q

Acidity increases as ___ EN and ___ EWG

A

Acidity increases as ↑ EN and ↑ EWG

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11
Q

Arrange the following based on increasing acid strength. Explain

CH3CH3, CH2=CH2, CH≡CH

A

CH3CH3 < CH2=CH2 < CH≡CH

↑ acidity as ↑ s character
single bond = 25% s
double bond = 33% s
triple bond = 50% s

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12
Q

How does a proton become an acidic proton?

A

It bears a partial positive charge because of its attachment to an electronegative atom or an electron withdrawing group

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13
Q

Differentiate aqua acid, hydroxoacid, and oxoacid in terms of (1) acidic proton (2) central atom

A
  1. Aqua acid [M(H2O)n]^m+
    → Lewis acid + Lewis base (H2O)
    → acidic proton is on the water ligand
    → metal center (d-block, group 2, or low oxidation metals)
  2. Hydroxoacid [M(OH)n]
    → acidic proton is on hydroxyl group w/o a neighboring oxo group
    → central atom is p-block or d-block element
  3. Oxoacid [OpE(OH)q]
    → acidic proton is on hydroxyl group with oxo group attached to same atom
    → nonmetal central atom
    → follows Pauling’s Rule
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14
Q

Pauling’s Rules for pKa values

A

pKa = 8 - 5p
pKa2 = pKa1 + 5
pKa3 = pKa2 + 5

Oxoacid [OpE(OH)q]
p = no. of oxo group (=O)
q = no. of acidic protons

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15
Q

Acidity of aqua acids (and hydroxoacids) increases with ____ ionic radius of central atom. Explain

A

↑ acidity ↓ ionic radius of central atom (M)

→ smaller central atom (M), higher charge density, shorter bond distance of M-O
→ M withdraw electrons from O more strongly
→ ↑ polarity of O-H bond in H2O (distance partial positive charge on H and partial negative charge on oxygen increases)
→ more positive acidic proton, easier to release

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16
Q

Acidity of hydroxoacids (and aqua acids) increases with ____ charge of central atom. Explain

A

↑ acidity ↑ charge of central atom

→ ↑ charge of central atom = more easily it withdraws electron from oxygen
→ ↑ polarity of O-H
→ more positive acidic proton, easier to release

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17
Q

Acidity of oxoacids increases with ____ electronegativity of central atom (E). Explain

A

↑ acidity ↑ EN of E

→ ↑ EN of E = easier to withdraw electrons from O of an OH group
→ ↑ polarity of O-H
→ more positive acidic proton, easier to release

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18
Q

Acidity of oxoacids increases with ____ no. of oxo groups. Explain

A

↑ acidity ↑ no. of oxo groups

→ electron withdrawing O weakens the O-H bond
→ ↑ polarity of O-H
→ more positive acidic proton, easier to release

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19
Q

Acidity of oxoacids increases with ____ resonance stabilziation of conjugate base.

A

↑ acidity ↑ stability of conj. base due to resonance

→ greater number of resonance contributions, more acidic

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20
Q

Nonmetal oxides such as CO2 are ____ in aqueous solution and in the form of ___

A

acidic
(H2CO3 in aq. sol’n)

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21
Q

Metal oxides such as BaO are ___ in aqueous solution and in the form of ____

A

basic
Ba(OH)2 in aq. sol’n

22
Q

Metalloid oxides such as Al2O3 are ___ in aqueous solution and in the form of ___

A

amphoteric
[Al(OH2)6]3+ and [Al(OH)4]-

23
Q

Arrange the following metal ions with increasing acid strength. Explain

K+, Na+, Al3+, Fe3+

A

K+ < Na+ < Al3+ < Fe3+

  1. K+, Na+ < Al3+, Fe3+
    → ↑ charge of metal ion = ↑ acid strength
    → attract electron pairs more
  2. K+ < Na+
    → ↓ ionic radius = ↑ acid strength
  3. Al3+ < Fe3+
    → Fe3+ has d orbitals
24
Q

Classify BF3 as acid or base. Explain

A

BF3 - Lewis acid
→ electron-deficient (incomplete octet)
→ electron acceptor

25
When comparing acidity of transition metals, acid strength increases as ____ increases
electronegativity ↑ acid strength ↑EN across the period
26
Explain the Lewis basicity down a group and across a period
Down a group: more basic (larger, loosely held electrons) Across a period: less basic (↑EN, electrons are held closer to nucleus, hard to lose) NOTE: for nonmetal elements
27
Define polarizability and polarizing power
Polarizability - degree to which a molecule or ion (anion) is distorted by its interaction with other molecules or ion Polarizing power - power of cation to polarize an anion
28
What is HSAB Theory
Hard and Soft Acids and Bases → predicts stability of products in Lewis acid-base reactions based on polarizability and charge density
29
Which species has high polarizing power and which has high polarizability?
High polarizing power: small, highly charged cations (+) High polarizability: large, highly charged anions and cations with no noble gas electron configuration
30
A 0.10 M solution of which substance is most acidic? NaHSO4, Na2SO4, NaHS
NaHSO4 - 2 oxo groups → MOST ACIDIC Na2SO4 - no ionizable H+ NaHS - no oxo group
31
Arrange the following in increasing covalent character: LiCl, NaCl, KCl, RbCl, CsCl
CsCl < RbCl < KCl < NaCl < LiCl larger cation = ionic = less covalent character
32
Arrange the following in increasing covalent character: LiF, LiCl, LiBr, Lil
LiF < LiCl < LiBr < Lil ↑ size of anion ↑ covalent character
33
Arrange the following in increasing covalent character: NaCl, MgCl2, AlCl3
NaCl < MgCl2 < AlCl3 ↑ charge on ions ↑ covalent character (more positive or more negative)
34
Which has greater covalent character? Explain ZnCl2 or CaCl2
ZnCl2 - greater covalent character → has pseudo-octet → total of 18 electrons → Zn2+: [Ar] 3d10 (8 + 10 e-) CaCl2 - more ionic character → octet → Ca2+: [Ar]
35
Describe hard and soft acids and bases in terms of polarizability, size, and charge
Hard Acid: strongly polarizing Hard Base: Weakly polarizable → ↓ size and ↑ charge Soft Acids: Weakly polarizing Soft Bases: Highly polarizable → ↑ size and ↓ charge
36
Hard base + hard acid forms ___ bond Soft acid + soft base forms ____
Hard base + hard acid forms stable ionic bond Soft acid + soft base forms stable covalent bond
37
Predict the direction of the reaction: LiI + CsF ____ LiF + CsI
Forward LiI (hard-soft) + CsF (soft-hard) → LiF (hard-hard) + CsI (soft-soft) → hard-hard and soft-soft bonds are more stable
38
Which halide is soluble? Explain AgF or AgI
AgF (soft-hard) is *soluble* soft-soft and hard-hard compounds are generally stable and form precipitates
39
Classify metal cations as hard, intermediate, and soft acids
Hard: All on the left of Cr, Nb, Hf All on the right of Al, Ga, Sn Intermediate: Forms a stage-like pattern from Ta, Mo, Mn ... Zn, In, Pb, Bi Soft: Ru ... Cd Os ... Tl
40
Classify nonmetal cations as hard, intermediate, and soft bases
Hard: N, O, F Intermediate: N, S, Cl Soft: All other nonmetals
41
Which of the following statements is true? A. NH3 is less basic than PH3. B. NH3 is more basic than PH3. C. NF3 is more basic than NH3. D. Both B and C are correct.
B. NH3 is more basic than PH3. periodic trend: pH (basicity) ←↑
42
The acidity of group 16 hydrides increases from H2O to H2Te (H2O << H2S < H2Se < H2Te). Which is the best explanation for this trend? A. The electronegativity of the group 16 elements increases going down the group. B. The polarizability of the group 16 elements increases going down the group. C. The polarity of the X-H bond increases going down the group. D. The H-X-H bond angle increases going down the group.
B. The polarizability of the group 16 elements increases going down the group. ↑ polarizability as ↑ size or ↑ charge
43
Which of the following is a weak Bronsted-Lowry acid? A. HCI B. HNO3 C. H2SO4 D. H2S
D. H2S → all other choices are included in six main strong acids HClO4, HNO3, H2SO4, HCl, HBr, HI
44
Which of the following is the strongest acid? A. HBrO B. HBrO2 C. HBrO3 D. HBrO4
D. HBrO4 ↑ oxo group ↑ acidity of oxoacids
45
The most acidic among the following oxoacids is: A. H2O B. HCIO C. HIO3 D. H3PO4
C. HIO3 A. H2O - not an oxoacid B. HCIO - 0 oxo group C. HIO3 - 2 oxo group D. H3PO4 - 1 oxo group
46
Which of the following compounds is a Lewis acid? A. NH3 B. AsH3 C. GaH3 D. GeH4
C. GaH3 Lewis acid - electron pair acceptor → A. NH3 and B. AsH3 are electron pair donor → D. GeH4 complete octet (similar to CH4)
47
Which of the following is the strongest Lewis acid? A. NF3 B. SbF5 C. NaCl D. PCl3
B. SbF5 Lewis acid - electron pair acceptor F- atoms increases positive character of Sb atom
48
Which of the following reactions is not consistent with Lewis acid-base theory? A. l2 + I- → [I3]- B. FeCl3 + CI- → [FeCl4]- C. Zn(s) +I3- → Zn2+ + 3I- D. SO3 + H2O → H+ + HSO4-
C. Zn(s) +I3- → Zn2+ + 3I- → redox reaction
49
Arrange the following cations in increasing acidity in water: Ca2+, Mn2+, Ni2+ A. Ni2+ < Mn2+ < Ca2+ B. Ca2+ < Mn2+ < Ni2+ C. Ca2+ < Ni2+ < Mn2+ D. Ni2+ < Ca2+ < Mn2+
B. Ca2+ < Mn2+ < Ni2+ kiM-CHIE **M**etal ion: ↑ **CH**arge M+, ↓ **I**onic radius, ↑ **E**lectronegativity = ↑ acidity
50
Predict which reaction will favor the formation of reactants. A. AgF + Lil ⇌ Agl + LiF B. CuBr2 + 2NaF ⇌ CuF2 + NaBr C. [AgCl2]- + 2CN- ⇌ [Ag(CN)2]- + 2Cl- D. Lil + CsF ⇌ LiF +Csl
B. CuBr2 + 2NaF ⇌ CuF2 + NaBr NaF - hard-hard (smaller) CuBr2 - soft-soft (bigger) hard-hard and soft-soft are more stable and favors the formation HARD - ↓ size ↑ charge SOFT - ↑ size ↓ charge
51
Differentiate the acidity vs size trend of metal cation (aquaacids) and nonmetal acids
Nonmetal: ↑ size atom → weaker H-X bonds → ↑ acidic Metal: ↓ size ion → higher charge density → ↑ acidic