group 7- reactions Flashcards
-equation for reaction of sodium fluoride with sulfuric acid
-what type of reaction is this
-how does sulfuric acid act as an acid
NaF + H2SO4 –> HF + NaHSO4
-acid base reaction- oxidation states dont change
-it donates protons
observation for reaction of sodium fluoride with sulfuric acid
steam white fumes of HF(g)
equation for reaction of sodium chloride with sulfuric acid
-what type of reaction is this
-how does sulfuric acid act as an acid
NaCl + H2SO4 –> HCl + NaHSO4
-acid base reaction- oxidation states dont change
-it donates protons
observation for reaction of sodium chloride with sulfuric acid
steamy white fumes of HCl(g)
equation for reaction of sodium bromide with sulfuric acid
-what type of reaction is this
NaBr + H2SO4 –> HBr + NaHSO4
-acid base reaction
observation for reaction of sodium bromide with sulfuric acid
-steamy white fumes of HBr
equation for reaction of hydrogen bromide with excess sulfuric acid
-which species is reducing agent- why
-which species is oxidising agent- why
2HBr + H2SO4 –> Br2 + SO2 + 2H2O
-Br- as it donates electrons
-H2SO4 as it accepts electrons
what is the change in oxidation state of S in the reaction of hydrogen bromide with excess sulfuric acid
+6 in H2SO4 to +4 in SO2
2 observations for reaction of hydrogen bromide with excess sulfuric acid and explain observations
-brown fumes of BR2 due to oxidation of Br-
-colourless choking gas of SO2 due to reduction of H2SO4
equation for reaction of sodium iodide with sulfuric acid
NaI + H2SO4 –> NaHSO4 + HI
observation for reaction of sodium iodide with sulfuric acid
steamy white fumes of HI(g)
equation for reaction of hydrogen iodide with excess sulfuric acid to produce SO2
2HI + H2SO4 –> I2 +SO2 + 2H2O
2 observations for reaction of hydrogen iodide with excess sulfuric acid to produce SO2 and explain observations
-black solid of I2 due to oxidation of I-
-colourless choking gas of SO2 due to reduction of H2SO4
equation for reaction of hydrogen iodide with excess sulfuric acid to produce S
6HI + H2SO4 –> 3I2 + S +4H2O
observation for reaction of hydrogen iodide with excess sulfuric acid to produce S and explain observation
-yellow solid of sulfur due to reduction of H2SO4
equation for reaction of hydrogen iodide with excess sulfuric acid to produce H2S
8HI + H2SO4 –> 4I2 + H2S + 4H2O
observation for reaction of hydrogen iodide with excess sulfuric acid to produce H2S and explain observation
-smell of bad eggs of H2S due to reduction of H2SO4
what is the change in oxidation state of S in the reaction of hydrogen iodide with excess sulfuric acid
+6 in H2SO4 to -2 in H2S
which halide ion reduces sulfur in sulfuric acid the most
I- reduces S from +6 in H2SO4 to -2 in H2S
how do displacement reactions work (2)
-adding a solution containing a halide ion to a solution containing a halogen
-more reactive halogen displaces less reactive halogen
what are the colours of halogens in aqueous solutions
chlorine solution= pale green
bromine solution= orange
iodine solution= brown
why cant iodine oxidise Cl-, Br- or I-
its a poor oxidising agent
3 ionic equations for displacement reactions
Cl2 + 2Br- –> Br2 + 2Cl-
Cl2 + 2I- –> I2 + 2Cl-
Br2 + 2I- –> I2 + 2Br-
what reagent used to test for halide ions
acidified silver nitrate
results for testing for halide ions
1.adding acidified silver nitrate
2. adding dilute NH3 to (1)precipitate
3.adding concentrated NH3 to (2)precipitate
1.adding acidified silver nitrate
F-(aq)= no precipitate
Cl-(aq)=white ppt of AgCl(s)
Br-(aq)=cream ppt of AgBr(s)
I-(aq)=yellow ppt of AgI(s)
2.adding dilute NH3 to (1)precipitate
AgCl(s)= ppt dissolves
AgBr(s)= ppt stays
AgI(s)= ppt stays
3.adding concentrated NH3 to (2)precipitate
AgBr(s)= ppt dissolves
AgI(s)= ppt stays
why is silver nitrate solution acidified
-its acidified with nitric acid
-prevents interference of CO3²⁻
-if CO3²⁻ were present theyd form a white ppt (misleading) and CO2 gas (test with limewater–>cloudy)
