Redox Reactions in Group 7 Flashcards
what will be the product of the reactions between the halogens and group 1 or 2 metals always form
salts
what agents are the halogens and metals
- the halogens are oxidising agents
- the metals are reducing agents
what are displacement reactions between halogens
when a more reactive halogen displaces a less reactive halogen from a compound
what would the products of chlorine + potassium bromide be
bromine + potassium chloride
what would the products of iodine + potassium fluoride be
iodine + potassium fluoride
how do you know when a displacement reaction has taken place
there would be an observable colour change
why should you add cyclohexane to a displacement reaction mixture
- halogens are more soluble in cyclohexane than in water
- so if you shake them together the halogen would dissolve in the upper layer
- so its colour can more easily be seen
what would the ionic equation of chlorine displacing bromine from sodium bromide be
- Cl2 + 2NaBr = Br2 + 2NaCl
- Cl2 + 2Br- = Br2 + 2Cl-
why are these kinds of reactions redox reactions
- the reacting halogen gains an electron
- while the reacting halide loses an electron
- therefore the reacting halogen is being reduced
- while the other is being oxidised
what are the two simple reasons why chlorine is more reactive than bromine or iodine
- it is the smallest atom
- so the incoming electron is more attracted by the nucleus
- it has the fewest few shells of electrons
- meaning it has the weakest shielding effect
what happens in disproportionation reactions
an element gets reduced and oxidised at the same time
why is the formation of hypochlorous acid, Cl2 + H2O = HCl + HClO, a disproportionation reaction for chlorine
- in HCl the Cl has an oxidation number of -1
- but in HClO it has an oxidation number of +1
- as O = -2 and H = +1
- this means that a chlorine molecule has been oxidised (HClO) and reduced (HCl) at the same time
what is formed when a halogen, lets say chlorine, is added to cold dilute aqueous sodium hydroxide
- it forms the usual halide salt (sodium chloride)
- a halate(I) / hypohalite salt (sodium hypochlorite / chlorate(I))
- and water
what would the equation be for the reaction between Cl2 and 2NaOH as well as the oxidation numbers of chlorine in the respective products
- Cl2 + 2NaOH = NaCl + NaClO + H2O
- in NaCl Cl = -1
- in NaClO Cl = +1
what is formed when a halogen like chlorine is added to hot concentrated sodium hydroxide solution
- the usual halide salt (sodium chloride)
- a halate(V) salt (sodium chlorate(V))
- and water
