1) hydrogen peroxide is an ra or oa? the equation when it is added to dye?
2)what is the oxidation number of Fe in Fe3O4, with explanation thz.
3)explain why chloine gas added into water is a disproportionation reaction.
4)why boron only combines with 3 flourine atom to form boron triflouride instead of
combining with 5 flourine atom to form boron pentaflourfide in order to obey the octet rule?
5)Isnt the boron triflouride unstable as it only has 6 electrons around boron?
You can either answer in English or Chinese, thanks for your help~~~~~
中四化學問題~redox ,non-octet(20P)
2014-04-15 5:07 am
回答 (2)
2014-04-15 7:53 am
✔ 最佳答案
1)Hydrogen can be used a reducing agent and also an oxidizing agent.
When acting as an reducing agent, hydrogen peroxide is oxidizing to oxygen gas,where the oxidation number of O increases from -1 to 0.
When acting as an oxidizing agent, hydrogen peroxide is reduced to water in anacidic medium or to hydroxide ion in an alkaline medium, where the oxidationnumber of O decreases from -1 to -2.
Hydrogen peroxide acts as an oxidizing agent when reacting with dye. Theequation is :
dye + H2O2 → [dye + O] + H2O
2)
The lattice of Fe3O4 contains both iron(II) ions and iron(III)ions in ratio 1 : 1. The formula of can be written as FeO•Fe2O3.
The oxidation number of Fe in FeO = +2
The oxidation number of Fe in Fe2O3 = +3
The oxidation number of Fe in Fe3O4 is +2 and +3.
3)
The equation of the reaction between chlorine gas and water :
Cl2 + H2O ⇌ HCl + HOCl
In the reduction of Cl2 to HCl, the oxidation number of Cl decreasesfrom 0 to -1.
In the oxidation of Cl2 to HOCl, the oxidation number of Clincreases from 0 to +1.
As Cl2 undergoes both oxidation and reduction, the reaction isdisproportionation.
4)
The electronic configuration of boron is B : 2, 3
Boron has only 3 outermost shell electrons. When boron reacts with fluorine,boron trifluoride (BF3) is formed. The 3 outermost shell electrons ofboron forms 3 covalent bonds with fluorine atoms.
5)
Boron trifluoride is unstable because it has only 6 electrons in the outermostshell of the central B atom, but not an octet. It can be stabilized to attainan octet by forming complex. Forexample, BF3 reacts with NH3 to form complex H3N→NF3.
參考: 土扁
2014-04-15 8:52 pm
1) "Hydrogen peroxide", not hydrogen.
5) Formation of dimer, forming 2 B-F (dative covalent) bonds: a fluorine atom on one molecule donates a lone pair to the boron on the other molecule.
2014-04-15 12:56:11 補充：
5) ooops nope, wikipedia says boron trihalides don't form dimers; aluminium halides do.
however, BF3 should not be very unstable due to the delocalization of electrons on fluorine to empty p-orbital of boron.
5) Formation of dimer, forming 2 B-F (dative covalent) bonds: a fluorine atom on one molecule donates a lone pair to the boron on the other molecule.
2014-04-15 12:56:11 補充：
5) ooops nope, wikipedia says boron trihalides don't form dimers; aluminium halides do.
however, BF3 should not be very unstable due to the delocalization of electrons on fluorine to empty p-orbital of boron.
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