Group 7

Question 1

Reducing ability of the Halides

Answer 1

Down the group reducing ability increases as outer electrons are lost more easily

Acid base- react with H2SO4 to form misty fumes

Redox- Br forms SO2 and Br2
I forms SO2, I2, S and H2S

Question 2

Chlorine

Answer 2

Chlorine water
Cl2+ H2O <-> HCl + HClO
This is a disproportion reaction as Cl2 is both oxidised and reduced.
turns indicator red then white

In sun
2Cl2 + 2H2O -> 4HCl + O2
Can be used to sterilise water

Question 3

Identification using silver nitrate the ammonia

Answer 3

AgNO3+NaX-> AgX +NaNO3
then ammonia

AgF AgCl are soluble in dilute ammonia
Agbr is soluble in concentrated ammonia
AgI isn’t soluble at all

Question 4

Oxidising ability of the halogens

Answer 4

Ability to act as an oxidising agent decreases because
atomic radius increases
shielding increases
so gains electrons less easily