Redox reactions in Group 7: displacement reactions Flashcards
reactions between group 1 or 2 elements with group 7 elements are most vigorous when the reactants are from the ………………of group 1 or 2 and the …………………of group 7 (top or bottom)
bottom of group 1 or 2 with top of group 7
when group 1 or 2 elements react with elements in group 7, a ……………is formed which is usually …………………in colour
form a white ionic solid salt
reactions between group 1 or 2 metals with a halogen involve an electron transfer to the
halogen
when reacting with group 1 or group 2 metals, the halogen’s oxidation number changes from………to………………
0 to -1
DECREASES
the equation for the reaction between lithium and chlorine is
2Li +Cl2 = 2LiCl
halogens can displace each other if
the halogen added to a mixture is more reactive than the halogen in the compound
displacement reactions for halogens occur in (conditions)
aqueous solution
halogen / halide displacement reactions involve an observable……….change
colour change due to the reaction being carried in aqueous solution
when carrying out halogen / halide displacement reactions, it is good to add …………………at the end to observe the colour change more clearly
add an organic solvent such as cyclohexane
why is the colour change for halogen / halide displacement reactions seen more clearly when cyclohexane is added
halogens are more soluble in cyclohexane than in water because of the polarity of the H2O molecules. when the halogen is displaced, it then dissolved into the cyclohexane to produce the distincive colour change
the colour change for when iodine is displaced is
pale orange/red to purple
the colour change for when bromine is displaced is
pale yellow to orange
the colour observed when chlorine dissolves in organic solvent is
pale green
chlorine displaces……………….and………………………….
bromine displaces…………………….but not………………
iodine does not displace…………….either………………
chlorine displaces bromine and iodine
bromine displaces iodine but not chlorine
iodine does not displace bromine either chlorine
two issues for interpreting colour changes for displacement reactions when water is the solvent are:
- some colours are similar in water (such as iodine and bromine)
- colours differ with concentration