Bukti halogen dan kondisi reaksi
Diperkenalkan| English | Makna |
|---|---|
| oxidising power | daya pengoksidasi |
| disproportionation/ˌdɪsprəˈpɔːʃəneɪʃn/ | disproporsionasi |
| aliquot/ˈælɪkwɒt/ | aliquot |
Why can the same halogen form different salts?
- Chlorine with cold dilute alkali forms hypochlorite. Hot concentrated alkali gives chlorate instead.
- Record conditions before balancing or interpreting oxidation numbers.
Predict displacement by electron gain
- Chlorine displaces bromide and iodide; bromine displaces iodide; iodine displaces neither.
- Down the group, greater radius and shielding weaken attraction to an incoming electron, lowering oxidising power 氧化能力.
Apa yang terjadi ketika bromin ditambahkan ke larutan iodida?
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Bromin adalah oksidator yang lebih kuat dan menerima elektron dari iodida.
Track disproportionation 歧化
- Cold dilute OH⁻: Cl₂ + 2OH⁻ → Cl⁻ + ClO⁻ + H₂O. Chlorine changes from 0 to −1 and +1.
- Hot concentrated OH⁻: 3Cl₂ + 6OH⁻ → 5Cl⁻ + ClO₃⁻ + 3H₂O. Chlorine changes from 0 to −1 and +5.
Cl₂ + 2Br⁻ → 2Cl⁻ + Br₂. Chlorine is reduced and is the oxidising agent; bromide is oxidised and is the reducing agent.
Temukan bilangan oksidasi klorin dalam ClO₃⁻. Gunakan oksigen = −2.
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x + 3(−2) = −1, sehingga x = +5.
Disproporsionasi mencakup oksidasi dan reduksi elemen yang sama dari satu spesies.
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Untuk klorin, atom yang awalnya bernilai nol menjadi memiliki bilangan oksidasi negatif dan positif.
Combine observations with a test
- Acidify halide solution with dilute HNO₃ before AgNO₃. AgCl is white, AgBr cream and AgI yellow.
- AgCl dissolves in dilute ammonia; AgBr requires concentrated ammonia; AgI remains. Use a separate aliquot 等分试样 for each independent test.
Endapan halogenida perak berwarna krem paling konsisten dengan ion halogenida mana? Tulis namanya.
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AgBr berwarna krem dan larut dalam amonia pekat, bukan amonia encer.
Keep colours and hazards in context
- Iodine is brown in water and violet in a suitable non-polar organic solvent. Its ordinary solid is grey-black.
- Chlorine water disinfects but needs controlled dosing. Concentrated-acid halide reactions and hazardous gas tests require the approved supervised method.
“A violet solution proves iodine in any solvent” is false. Solvent affects the observed colour; aqueous iodine is brown.
State the reagent, temperature, concentration and solvent when they change the product or observation.
Dua klaim manakah yang benar?
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Pelarut dan kondisi alkali menentukan pengamatan ini. HCl mencemari uji halogenida; asam dapat melepaskan klorin berbahaya dari pemutih.