2.3 Halogens Flashcards
What is the affect of adding AgNO3- to F-
No precipitate as silver fluoride is soluble
What is the affect and equation of adding AgNO3- to Cl-?
White Precipitate
Ag+ + Cl- —> AgCl (s)
What is the action of dilute NH3 on AgCl and what is the equation?
Solid precipitate dissolves
AgCl + 2NH3 >< [Ag(NH3)2]+ + Cl-
What is the action of AgNO3- on Br- and what is the equation?
Cream precipitate
Ag+ + Br- —> AgBr (s)
What is the effect of dilute NH3 on AgBr?
No effect
What is the effect of concentrated NH3 on AgBr?
Solid precipitate dissolves
What is the effect of AgNO3 on I-?
Yellow precipitate
What effects does NH3 have on AgI?
None
What are the features of fluorine ?
Yellow gas
Very reactive
Toxic
What are the features of chlorine?
Green gas
Still quite reactive
Very toxic
What are the features of bromine?
Brown liquid
Easily forms orange vapour
What are the features of iodine?
Grey crystalline solid
Forms purple Vapour (sublimates)
What is the equation for chlorine in water?
Cl2 +H2O >< HCl + HClO
HClO = Chloric 1 acid
What is the equation for chlorine in water left in sunshine?
2Cl2 + H2O —> 4HCl + O2
What is the equation for Cl2 in cold dilute NaOH?
Cl2 + 2NaOH —> NaCl + NaClO + H2O
Which Halogen is the best reducing agent and why?
Iodine because atoms get larger which increases the shielding and outer electrons are more easily lost
Which halogen is the best oxidising agent?
Fluorine
What are the products and observations of H2SO4 and Cl-?
HCl
White Steamy fumes
What is produced when NaBr reacts with H2SO4?
HBr= White steamy fumes
SO2= Colourless gas
Br2
What are the products when NaI + H2SO4?
- HI- White steamy fumes
- SO2- Colourless gas
- I2
- Sulfur- Yellow solid
-H2S- Choking gas
What is disproportionation?
When an element oxidises and reduces at the same time
E.g Cl and H2O
