Halogens Topic 4 Flashcards
What is the trend in melting and boiling points of the halogens going down the group?
Melting and Boiling points increase going down the group
What is the trend in electronegativity going down group 7?
Electronegativity decreases going down the group
Reaction between sodium fluoride and sulfuric acid
NaF + H2SO4 —> NaHSO4 + HF
reaction between sodium chloride and sulfuric acid
NaCl + H2SO4 —> NaHSO4 + HCl
What is the trend in solubility of Group 2 Hydroxides?
Solubility of group 2 hydroxides increases going down the group
What is the trend of group 2 sulphates? in solubility
Solubility decreases going down the group therefore Barium Sulfate is the most insoluble
Test for sulfate ions
Using acidified Barium Chloride
White precipitate if sulphates present
Testing for carbonates
Adding acid (HCl) will produce CO2 gas.
Can be collected and bubbled through limewater which will turn cloudy confirming CO2 is present
Testing for cations (ammonium)
Adding warm NaOH will create ammonia gas
-ammonia can be tested if damp red litmus paper turns blue
Testing for cations (ammonium)
Adding warm NaOH will create ammonia gas
-ammonia can be tested if damp red litmus paper turns blue
Oxidising power of halogens trend
Decreases going down the group due to electrons and shielding increasing down the group
the disproportionation reaction of chlorine with water equation
Cl2 + H2O <–> HCl + HClO
the disproportionation reaction of chlorine with cold, dilute aqueous sodium hydroxide to form bleach
Cl2 + 2NaOH –> NaClO + NaCl + H2O
equation for disproportionation reaction between chlorine and hot alkali
3Cl2 + 6NaOH —> 5NaClO3 + NaClO + 3H2O
Test for when dilute aqueous ammonia is added to Bromide
Bromide is insoluble
