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Inorganic QA (identify from test results) Flashcards

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1
Q

Upon addition of NaOH(aq), no ppt formed. What could it be?

A

K⁺, Na⁺, Ba²⁺
Effervescence observed:
- NH3 upon heating: NH4⁺
- H2: Zn or Al in water

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2
Q

What is the equation for NH4⁺ upon addition of NaOH(aq)?

A

NH4⁺ (aq) + OH⁻ (aq) → NH3 (g)+ H2O (l)

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3
Q

What is the equation of Al in water upon addition of NaOH(aq)?

A

2Al (s) + 2OH⁻ (aq) + 6H2O (l)→ 3H2 (g)+ 2[Al(OH)4]⁻ (aq)

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4
Q

What is the equation of Zn in water upon addition of NaOH(aq)?

A

Zn (s) + 2OH⁻ (aq) + 2H2O (l) → [Zn(OH)₄]²⁻ (aq) + H2 (g)

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5
Q

Upon addition of NaOH(aq), white ppt. formed. What could it be?

A
  • Ppt. soluble in excess NaOH to form colourless solution: Al³⁺, Zn²⁺
  • Ppt. insoluble in excess NaOH: Ca²⁺, Mg²⁺
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6
Q

What is the equation of Al³⁺ upon addition of NaOH(aq)?

A

Al³⁺ (aq) + 3OH⁻ (aq) → Al(OH)₃ (s)
Al(OH)₃ (s) + OH⁻ (aq) → [Al(OH)₄]⁻ (aq)

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7
Q

What is the equation of Zn²⁺ upon addition of NaOH(aq)?

A

Zn²⁺ (aq) + 2OH⁻ (aq) → Zn(OH)₂ (s)
Zn(OH)₂ (s) + 2OH⁻ (aq) → [Zn(OH)₄]²⁻ (aq)

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8
Q

What is the equation of Ca²⁺ upon addition of NaOH(aq)?

A

Ca²⁺ (aq) + 2OH⁻ (aq) → Ca(OH)₂ (s)

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9
Q

What is the equation of Mg²⁺ upon addition of NaOH(aq)?

A

Mg²⁺ (aq) + 2OH⁻ (aq) → Mg(OH)₂ (s)

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10
Q

Upon addition of NaOH(aq), cream ppt. formed. What could it be?

A

Ppt. insoluble in excess NaOH (aq), ppt. turned brown on standing in air: Mn²⁺

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11
Q

What is the equation of Mn²⁺ upon addition of NaOH(aq)?

A

Mn²⁺ (aq) + 2OH⁻ (aq) → Mn(OH)₂ (s)
4Mn(OH)₂ (s) + O₂ (g) +2H2O (l) → 4Mn(OH)₃ (s)
{oxidation}

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12
Q

Upon addition of NaOH(aq), grey-green ppt. formed. What could it be?

A

Ppt. soluble in excess NaOH(aq) to form a dark green solution: Cr³⁺

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13
Q

What is the equation of Cr³⁺ upon addition of NaOH(aq)?

A

Cr³⁺ (aq) + 3OH⁻ (aq) → Cr(OH)₃ (s)
Cr(OH)₃ (s) + 3OH⁻ (aq) → [Cr(OH)₆]³⁻ (aq)

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14
Q

Upon addition of NaOH(aq), green ppt. formed. What could it be?

A

Ppt. insoluble in excess NaOH(aq), ppt. turned brown on standing in air: Fe²⁺

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15
Q

What is the equation of Fe²⁺ upon addition of NaOH(aq)?

A

Fe²⁺ (aq) + 2OH⁻ (aq) → Fe(OH)₂ (s)
4Fe(OH)₂ (s) + O₂ (g) +2H2O (l) → 4Fe(OH)₃ (s)
{oxidation}

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16
Q

Upon addition of NaOH(aq), red-brown ppt. formed. What could it be?

A

Ppt. insoluble in excess: Fe³⁺

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17
Q

What is the equation of Fe³⁺ upon addition of NaOH(aq)?

A

Fe³⁺ (aq) + 3OH⁻ (aq) → Fe(OH)₃ (s)

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18
Q

Upon addition of NaOH(aq), pale blue ppt. formed. What could it be?

A

Ppt. insoluble in excess, ppt. turned black upon boiling: Cu²⁺

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19
Q

Upon addition of NH₃(aq), no ppt. formed. What could it be?

A

Ba²⁺, Ca²⁺ , NH4⁺

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20
Q

Upon addition of NH₃(aq), white ppt. formed. What could it be?

A
  • Soluble in excess to give a colourless solution: Zn²⁺
  • Insoluble in excess: Al³⁺, Mg²⁺
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21
Q

What is the equation of Zn²⁺ upon addition of NH₃(aq)?

A

NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq)

Zn²⁺ (aq) + 2OH⁻ (aq) → Zn(OH)₂ (s)

Zn(OH)₂ (s) + 4NH₃ (aq) → [Zn(NH₃)₄]²⁺ (aq) + 2OH⁻ (aq)

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22
Q

What is the equation of Al³⁺ upon addition of NH₃(aq)?

A

NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq)
Al³⁺ (aq) + 3OH⁻ (aq) → Al(OH)₃ (s)

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23
Q

What is the equation of Mg²⁺ upon addition of NH₃(aq)?

A

NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq)
Mg²⁺ (aq) + 2OH⁻ (aq) → Mg(OH)₂ (s)

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24
Q

Upon addition of NH₃(aq), off-white ppt. formed. What could it be?

A

ppt. insoluble in excess NH3(aq), ppt. turned brown on standing in air: Mn²⁺

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25
What is the equation of Mn²⁺ upon addition of NH₃(aq)?
NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq) Mn²⁺ (aq) + 2OH⁻ (aq) → Mn(OH)₂ (s) 4Mn(OH)₂ (s) + O₂ (g) +2H2O (l) → 4Mn(OH)₃ (s) {oxidation}
26
Upon addition of NH₃(aq), grey-green ppt. formed. What could it be?
Ppt. insoluble in excess NH3: Cr³⁺
27
What is the equation of Cr³⁺ upon addition of NH₃(aq)?
NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq) Cr³⁺ (aq) + 3OH⁻ (aq) → Cr(OH)₃ (s)
28
Upon addition of NH₃(aq), green ppt. formed. What could it be?
ppt. insoluble in excess NH3(aq), ppt. turned brown on standing in air: Fe²⁺
29
What is the equation of Fe²⁺ upon addition of NH₃(aq)?
NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq) Fe²⁺ (aq) + 2OH⁻ (aq) → Fe(OH)₂ (s) 4Fe(OH)₂ (s) + O₂ (g) +2H2O (l) → 4Fe(OH)₃ (s) {oxidation}
30
Upon addition of NH₃(aq), red-brown ppt. formed. What could it be?
ppt. insoluble in excess NH3(aq): Fe³⁺
31
What is the equation of Fe³⁺ upon addition of NH₃(aq)?
NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq) Fe³⁺ (aq) + 3OH⁻ (aq) → Fe(OH)₃ (s)
32
Upon addition of NH₃(aq), blue ppt. formed. What could it be?
ppt. soluble in excess to form a dark blue solution: Cu²⁺
33
What is the equation of Cu²⁺ upon addition of NH₃(aq)?
NH₃(aq) + H2O (l) ⇌ NH4⁺ (aq) + OH⁻ (aq) Cu²⁺ (aq) + 2OH⁻ (aq) → Cu(OH)₂ (s) Cu(OH)₂ (s) + 2H2O (l) + 4NH3 (aq) → [Cu(NH3)₄(H2O)₂]²⁺ (aq) + 2OH⁻ (aq)
34
Why is there no ppt. produced upon adding NH3 in Ca²⁺ solution but white ppt. produced upon adding NaOH?
NH₃ is a relatively weak base with lower [OH⁻] compared than NaOH, it does not precipitate hydroxides of relatively high solubility product
35
Upon addition of Na₂CO₃ (aq), no ppt. formed. What could it be?
Upon warming, effervescence observed. Colourless and pungent gas turns moist red litmus paper blue, NH3(g) evolved: NH₄⁺
36
What is the equation of Cu²⁺ upon addition of NaOH(aq)?
Cu²⁺ (aq) + 2OH⁻ (aq) → Cu(OH)₂ (s) Cu(OH)₂ → CuO (s) + H2O (l){decomposition}
37
What is the equation of NH₄⁺ upon addition of Na₂CO₃ (aq)?
CO₃²⁻ (aq) + H2O (l) ⇌ HCO3⁻ (aq) + OH⁻ (aq) NH4⁺ (aq) + OH⁻ (aq) → NH3 (g) + H2O (l)
38
Upon addition of Na₂CO₃ (aq), white ppt. formed. What could it be?
Ppt. insoluble in excess: Ba²⁺, Ca²⁺, Mg²⁺, Zn²⁺ Effervescence observed, white ppt. formed with a colourless, odourless gas that gave white ppt. with limewater, CO2 evolved: Al³⁺
39
What is the equation of Al³⁺ upon addition of Na₂CO₃ (aq)?
Hydrolysis occurs due to high charge density: [Al(H₂O)₆]³⁺ (aq) ⇌ [Al(H₂O)₅OH]²⁺ (aq) + H⁺ (aq) CO₃²⁻ (aq) + 2H⁺ (aq) → CO₂ (g) + H₂O (l) Removal of H⁺ shifts the position of equilibrium of hydrolysis to the right 2[Al(H₂O)₆]³⁺ (aq) + 2CO₃²⁻ (aq) → 2[Al(H₂O)₃(OH)₃] (s) + 3CO₂ (g) + 3H₂O (l)
40
Upon addition of Na₂CO₃ (aq), off-white ppt. formed. What could it be?
Ppt. turned brown on heating: Mn²⁺
41
What is the equation of Mn²⁺ upon addition of Na₂CO₃ (aq)?
Mn²⁺ (aq) + CO₃²⁻ (aq) → MnCO₃ (s) 2MnCO₃ (s) + O₂ (g) → 2MnO₂ (s) + 2CO₂ (g) {oxidation}
42
What is the equation of Ba²⁺ upon addition of Na₂CO₃ (aq)?
Ba²⁺ (aq) + CO₃²⁻ (aq) → BaCO₃ (s)
43
What is the equation of Ca²⁺ upon addition of Na₂CO₃ (aq)?
Ca²⁺ (aq) + CO₃²⁻ (aq) → CaCO₃ (s)
44
What is the equation of Mg²⁺ upon addition of Na₂CO₃ (aq)?
Mg²⁺ (aq) + CO₃²⁻ (aq) → MgCO₃ (s)
45
What is the equation of Zn²⁺ upon addition of Na₂CO₃ (aq)?
Zn²⁺ (aq) + CO₃²⁻ (aq) → ZnCO₃ (s)
46
Upon addition of Na₂CO₃ (aq), grey-green ppt. formed. What could it be?
Colourless and odourless gas gave white ppt. with limewater, CO2 (g) evolved: Cr³⁺
47
What is the equation of Cr³⁺ upon addition of Na₂CO₃ (aq)?
Hydrolysis occurs due to high charge density: [Cr(H₂O)₆]³⁺ (aq) ⇌ [Cr(H₂O)₅OH]²⁺ (aq) + H⁺ (aq) CO₃²⁻ (aq) + 2H⁺ (aq) → CO₂ (g) + H₂O (l) Removal of H⁺ shifts the position of equilibrium of hydrolysis to the right 2[Cr(H₂O)₆]³⁺ (aq) + 2CO₃²⁻ (aq) → 2[Cr(H₂O)₃(OH)₃] (s) + 3CO₂ (g) + 3H₂O (l)
48
Upon addition of Na₂CO₃ (aq), green ppt. formed. What could it be?
Ppt. insoluble in excess: Fe²⁺
49
What is the equation of Fe²⁺ upon addition of Na₂CO₃ (aq)?
Fe²⁺ (aq) + CO₃²⁻ (aq) → FeCO₃ (s)
50
Upon addition of Na₂CO₃ (aq), blue ppt. formed. What could it be?
Ppt. turned black on boiling: Cu²⁺
51
What is the equation of Cu²⁺ upon addition of Na₂CO₃ (aq)?
Cu²⁺ (aq) + CO₃²⁻ (aq) → CuCO₃ (s) Upon heating: CuCO₃ (s) → CuO (s) + CO₂ (g)
52
Upon addition of Na₂CO₃ (aq), red-brown ppt. formed. What could it be?
Effervescence observed, colourless and odourless gas evolved gave white ppt. in limewater, CO₂ (g) evolved: Fe³⁺
53
What is the equation of Fe³⁺ upon addition of Na₂CO₃ (aq)?
Hydrolysis occurs due to high charge density: [Fe(H₂O)₆]³⁺ (aq) ⇌ [Fe(H₂O)₅OH]²⁺ (aq) + H⁺ (aq) CO₃²⁻ (aq) + 2H⁺ (aq) → CO₂ (g) + H₂O (l) Removal of H⁺ shifts the position of equilibrium of hydrolysis to the right 2[Fe(H₂O)₆]³⁺ (aq) + 2CO₃²⁻ (aq) → 2[Fe(H₂O)₃(OH)₃] (s) + 3CO₂ (g) + 3H₂O (l)
54
Why upon addition of Na₂CO₃ (aq), some metal cations form insoluble hydroxides instead of carbonates?
Metal cations with high charge density (Fe³⁺, Cr³⁺, Al³⁺) have highly polarising cations that distort the electron clouds of the water molecules in the hexaaqua metal complex, thus weakening their O-H bonds, thus these cations hydrolyses in water to produce H₃O⁺
55
Upon addition of AgNO₃ (aq), white ppt. formed. What could it be?
- Ppt. turned yellow-brown on standing, ppt. soluble in dilute HNO₃ (aq), CO₂ (g) evolved: CO₃²⁻ - ppt. soluble in HNO₃, SO₂ (g) evolved: SO₃²⁻ - ppt. insoluble in HNO₃: SO₄²⁻ or Cl⁻ * Add excess NH₃(aq): ppt. soluble in excess NH₃ (aq) to give a colourless solution [Ag(NH₃)₂]⁺: Cl⁻
56
What is the equation when you add excess NH3(aq) into AgX (aq)?
* AgX (s) ⇌ Ag⁺ (aq) + X⁻ (aq) * Ag⁺ (aq) + 2NH₃ (aq) ⇌ [Ag(NH₃)₂]⁺ (aq)
57
Upon addition of AgNO₃ (aq), cream ppt. formed. What could it be?
* Ppt. insoluble in dilute HNO₃ * Ppt. partially soluble in excess NH₃ (aq) to give a colourless solution of [Ag(NH₃)₂]⁺: Br⁻
58
Upon addition of AgNO₃ (aq), yellow ppt. formed. What could it be?
* ppt. insoluble in dilute HNO₃ * ppt. insoluble in NH₃ (aq): I⁻
59
Upon addition of AgNO₃ (aq), red-brown ppt. formed. What could it be?
CrO₄²⁻
60
What happens when Ag₂SO₃ is warmed?
Observation: SO2 evolved Equation: 2Ag₂SO₃ (s) → 2Ag(s) + Ag₂SO₄ (s) + SO₂ (g)
61
What happens when you expose white ppt. of AgCl (s) to light or left to stand?
Observation: Cl2 evolved Equation: 2AgCl (s) → 2Ag(s) + Cl₂ (g)
62
Upon addition of KMnO₄ (aq), solution remains purple. What could it be?
Observation: effervescence observed, white ppt. formed with limewater, CO₂ evolved: CO₃²⁻
63
Upon addition of KMnO₄ (aq), purple KMnO₄ decolourises. What could it be?
* Cl₂ evolved; greenish-yellow pungent gas evolved turned moist blue litmus red then bleached it: Cl⁻ * Br₂ evolved; reddish-brown pungent gas evolved fromed an orange solution when passed into water, orange solution turned colourless on addition of NaOH (aq): Br⁻ * Black deposits in brown solution formed: I⁻ * Add K₂Cr₂O₇ (aq): orange Cr₂O₇²⁻ turned green Cr³⁺: NO₂⁻ or SO₃²⁻
64
Upon addition of Pb(NO₃)₂ (aq), white ppt. formed. What could it be?
* soluble in dilute acid and CO₂ evolved: CO₃²⁻ * ppt. soluble in hot water to give a colourless solution, ppt. reappeared upon cooling: Cl⁻ or Br⁻ * ppt. soluble in conc. HCl to give a colourless solution of [PbCl₄]²⁻: Cl⁻ * ppt. insoluble in hot water ppt. soluble in dilute acids to give SO₃: SO₃²⁻ * ppt. insoluble in hot water ppt. insoluble in strong dilute acids: SO₄²⁻
65
Upon addition of Pb(NO₃)₂ (aq), yellow ppt. formed. What could it be?
* ppt. soluble in dilute acids to give an orange solution: CrO₄²⁻ * ppt. soluble in hot water to give a colourless solution, ppt. reappeared as golden crystals upon cooling: I⁻
66
What can KI (aq) be used for?
* as a reducing agent (to test for oxidising agent) * as a precipitant
67
How to prepare KI to test for precipitant?
To about 1-2cm³ of aqueous test sample, add a few drops of KI (aq)
68
How to prepare KI to test as a reducing agent (test for oxidising agent)?
- Add approximately equal volume of dilute H₂SO₄ to 1-2cm³ of the test sample (if acidic condition is required) - Add KI (aq) dropwise until no more change is observed (basically acidified KI)
69
Upon addition of acidified KI (aq), cream ppt. formed in brown solution. What could it be? | Additional tests, equation
* 2Cu²⁺ (aq) + 4I⁻ (aq) → 2CuI (s) + I₂ (aq) * On addition, of NaS₂O₃ (aq), brown solution turned colourless: Cu²⁺ * 2S₂O₃²⁻ + I₂ (aq) → S₄O₆²⁻ (aq) + 2I⁻ (aq)
70
What can K₂Cr₂O₇ (aq) be used to test for?
* precipitate insoluble chromate(VI) * test for acidic solutions
71
Upon addition of acidified K₂Cr₂O₇ (aq), yellow ppt. formed. What could it be? | Additional test
ppt. insoluble in NaOH (aq): Ba²⁺
72
Upon addition of acidified K₂Cr₂O₇ (aq), brown ppt. formed. What could it be?
Cu²⁺
73
Upon addition of acidified K₂Cr₂O₇ (aq), orange-brown ppt. formed. What could it be?
Fe³⁺
74
Upon addition of acidified K₂Cr₂O₇ (aq), solution turns from orange to yellow. What does this mean?
Solution is alkali Cr₂O₇²⁻ (aq) + 2OH⁻ (aq) → 2CrO₄²⁻ (aq) + H₂O (l) (Reverse can also work if solution is acidic)
75
Upon addition of BaCl₂ (aq) or Ba(NO₃)₂ (aq), followed by dilute acids, white ppt. formed. What could it be?
* ppt. soluble in dilute acids * CO₂ (g) evolved: CO₃²⁻ * SO₂ (g) evolved: SO₃²⁻ * ppt. insoluble in dilute acids: SO₄²⁻
76
Upon addition of BaCl₂ (aq) or Ba(NO₃)₂ (aq), followed by dilute acids, yellow ppt. formed. What could it be?
-ppt. soluble in dilute acids to give orange solution: CrO₄²⁻
77
What can HCl (aq) or H₂SO₄ (aq) be used for?
1. Cation test 2. Anion test 3. Redox reagent 4. HCl test for strong oxidising agent 5. H₂SO₄ (aq) provide acidic medium for redox reaction
78
Upon addition of HCl (aq) or H₂SO₄ (aq), white ppt. formed. What could it be?
Ag⁺, Pb²⁺, Ba²⁺
79
What are the possible observations when HCl (aq) or H₂SO₄ (aq) is used to test for anions?
* CO₂ (g) evolved: CO₃²⁻ * SO₂ (g) evolved: SO₃²⁻ * NO₂ (g) evolved: NO₂⁻ * orange solution turned yellow: CrO₄²⁻
80
How can HCl (aq) be used to test for strong oxidising agents?
HCl can be an oxidising or reducing agent, with a strong oxidising agent, it will be oxidised
81
Why is H₂SO₄ (aq) used to provide acidic medium instead of HNO₃ or HCl?
* HNO₃ is oxidising agent * HCl can be oxidised by strong oxidising agents, HCl itself also can be oxidising agent
82
How to test for water vapour?
Colourless, odourless gas that turned blue cobalt(II) chloride paper pink
83
How to test for NO2 (g)?
- Brown, pungent gas turned moist blue litmus paper red - turn FeSO₄ from pale green to brown
84
How to test for HCl (g)?
Colourless, pungent gas that turns moist blue litmus paper red and forms dense white fumes with NH₃ gas
85
How to test for Br₂ (g)?
- Reddish-brown, pungent gas that forms an orange solution when passed into water - The orange solution turned colourless on addition of NaOH (aq)
86
In general, what are the possible deductions and observations upon adding NaOH (aq)?
- identify cations from colour of ppt. and solubility in excess - confirm presence of NH₄⁺
87
In general, what are the possible deductions and observations upon adding NH₃ (aq)?
identify cations from colour of ppt. and solubility in excess
88
In general, what are the possible deductions and observations upon adding NH₃ (aq)?
- ppt. formed (colour) - gas evolved: NH₃, CO₂
89
In general, what are the possible deductions and observations upon adding dilute HCl or dilute H₂SO₄?
- ppt. formed (colour) - gas evolved: CO₂, SO₂, NO₂ (or H₂ if metal is present)
90
In general, what are the possible deductions and observations upon adding KI (aq)?
- ppt. formed (colour) - yellow or black deposits in brown solution due to liberation of I₂ in presence of oxidising agent
91
In general, what are the possible deductions and observations upon adding K₂Cr₂O₇ (aq)?
- ppt. formed (colour) - colour change of the solution
92
In general, what are the possible deductions and observations upon adding AgNO₃ (aq)?
- ppt. formed (colour) - solubility of ppt. in NH₃ (aq) and/or dilute acid and gas evolved
93
In general, what are the possible deductions and observations upon adding BaCl₂ or Ba(NO₃)₂ (aq)?
- ppt. formed - solubility of ppt. formed in HCl (aq) and gas evolved
94
In general, what are the possible deductions and observations upon adding Pb(NO₃)₂ (aq)?
- ppt. formed - solubility of ppt. in hot water and/or acids
95
In general, what are the possible deductions and observations upon adding KMnO₄ (aq)?
Colour change of solution
96
What happens when you add conc. HCl dropwise to Cu²⁺ (aq)? | Observation and Equation
* Blue solution turned green then yellow (or yellow-green solution obtained) * [Cu(H₂O)₆]²⁺ (aq) + 4Cl⁻ (aq) ⇌ [CuCl₄]²⁻ (aq) + 6H₂O (l) * green is due to mixture of [Cu(H₂O)₆]²⁺ and [CuCl₄]²⁻
97
What happens when you add NaOH (aq) until ppt. dissolves followed by heating with H₂O₂(aq) to Cr³⁺ (aq)?
* grey-green ppt. formed, ppt. soluble in excess NaOH(aq) to give a dark green solution [Cr(OH)₆]³⁻ (aq) * Cr³⁺ (aq) + 3OH⁻ (aq) → Cr(OH)₃ (s) * Cr³⁺ (aq) + 6OH⁻ (aq) → [Cr(H₂O)₆]³⁻ (aq) * Upon heating with H₂O₂(aq), a yellow solution formed * 2[Cr(H₂O)₆]³⁻ (aq) + 3H₂O₂(aq) → 2CrO₄²⁻ (aq) + 8H₂O(l) + 2OH⁻ (aq)
98
What happens when you add KSCN(aq) dropwise to Fe³⁺ (aq)?
* Blood-red colouration observed * [Fe(H₂O)₆]³⁺ (aq) + SCN⁻ (aq) → [Fe(SCN)(H₂O)₅]²⁺ (aq) + H₂O (l)
99
What happens when you add NH₃(aq) followed by adding NH₄Cl(aq) dropwise till excess to Mg²⁺ (aq)?
* white ppt. of Mg(OH)₂ formed * ppt. insoluble in NH₃(aq) * ppt. soluble in NH₄⁺ (aq)
100
What happens when you add NH₃(aq) followed by adding NH₄Cl(aq) dropwise till excess to Mn²⁺ (aq)?
* cream ppt. of Mn(OH)₂ formed * ppt. insoluble in NH₃(aq) * ppt. soluble in NH₄⁺ (aq)
101
What happens when you heat NO₃⁻ or NO₂⁻?
Brown pungent gas evolved turned moist blue litmus red, NO₂ (g) evolved
102
What happens when you add NaOH(aq) and Al or Zn powder or Devarda's alloy to NO₃⁻ and warm mixture gently?
Colourless, pungent gas evolved turned moist red litmus paper blue, NH₃ (g) evolved (H₂ is always evolved when NaOH is added to Al or Zn or Devarda's alloy)
102
What happens when you heat CO₃²⁻?
Colourless, odourless gas evolved formed white ppt. with limewater, CO₂ (g) evolved
103
What happens when you add NaOH(aq) and Al or Zn powder or Devarda's alloy to NO₂⁻ and warm mixture gently?
Colourless, pungent gas evolved turned moist red litmus paper blue, NH₃ (g) evolved (H₂ is always evolved when NaOH is added to Al or Zn or Devarda's alloy)
104
What happens when you add NaOCl(aq), followed by ethanoic acid CH₃COOH to Br⁻ and add a few drops of organic solvent to the mixture and shake?
* Orange solution Br₂ (aq) formed * Organic solvent layer turned orange-red
105
What happens when you add solid MnO₂ and conc. H₂SO₄ to solid sample containing Cl⁻?
greenish-yellow pungent gas evolved turned moist blue litmus red then bleached it, Cl₂ (g) evolved
105
What happens when NaOCl(aq), followed by CH₃COOH is added to I⁻, then a few drops of organic solvent is added to mixture and shake?
* Brown solution I₂ (aq) formed * Organic solvent layer turned violet
106
What happens when CuSO₄ (aq) is added to I⁻ and then Na₂S₂O₃ (aq) is added till in excess?
* cream ppt. CuI (s) in brown solution I₂ (aq) formed * On adding N₂S₂O₃ (aq), brown solution decolourised (I⁻)
107
What happens when dilute HCl is added to I⁻ followed by H₂O₂(aq)?
Black deposits in brown solution formed (I₂ liberated)

Chemistry Practical (4 decks)

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