Group 7 Halogens

Question 1

Trend in atomic radius from F to I

Answer 1

Increases

Question 2

Trend in boiling point from F to I

Answer 2

Increased

Question 3

Trend in electronegativity from F to I

Answer 3

Decreases

Question 4

Trend in oxidising power from F to I (explain)

Answer 4

Decreases.
The oxidising ability is linked to the size of the halogen.
Smaller halogens are more electronegative (because smaller distance btw nucleus + outer shell)
Therefore they have a better ability of gaining electrons.

Question 5

Displacement reaction between Br2 and Cl-

Answer 5

Stays yellow (no reaction)

Question 6

Displacement reaction between I2 and Cl-

Answer 6

Stays brown (no reaction)

Question 7

Displacement reaction between Cl2 and Br-

Answer 7

Yellow solution (Br2) formed. 
Cl2 + 2Br- —> 2Cl- + Br2

Question 8

Displacement reaction between I2 and Br-

Answer 8

Stays brown solution (no reaction)

Question 9

Displacement reaction between Cl2 and I-

Answer 9

Brown solution (I2) formed. 
Cl2 + 2I- —> 2Cl- + I2

Question 10

Displacement reaction between Br2 and I-

Answer 10

Brown solution (I2) formed. 
Br2 +2I- —> 2Br- +I2

Question 11

Trend in reducing ability from F to I

Answer 11

Increases

Question 12

NaCl + H2SO4 (observation, product(s), type of reaction)

Answer 12

Observe - steamy fumes
Product - HCl
Reaction - Acid-Base

Question 13

NaBr + H2SO4 (observation, product(s), type of reaction)

Answer 13

Steamy fumes (HBr) (Acid-Base)
Brown fumes (Br2) (Redox)
Colourless gas (SO2) (Redox)

Question 14

NaI + H2SO4 (observation, product(s), type of reaction)

Answer 14

Steamy fumes (HI) (Acid-Base)
Purple fumes/Black solid (I2) (Redox)
Colourless gas (SO2) (Redox)
Yellow solid (S) (Redox)
Bad egg smell (H2S) (Redox)

Question 15

Chlorine in water (equation)

Answer 15

Cl2 + H2O HCl + HOCl

Disproportionation

Question 16

Observation of pH paper in chlorine water

Answer 16

Turns red (because acidic) then bleaches white

Question 17

Uses of chlorine

Answer 17

In swimming pools + drinking water to kill bacteria + disinfect/sterilise water

Question 18

Chlorine with cold NaOH (aq) (equation + use)

Answer 18

Cl2 + 2NaOH —> NaCl + NaOCl + H2O

(Disproportionation)

Products used commercially for bleach