Group 7-halogens

Question 1

what happens to the boiling point of halogens

Answer 1

decrease down the group, vvw forces increases in strength, lower the bp the more volatile the element

Question 2

what is the trend in electronegativity

Answer 2

decreases down the group , larger atoms attract electrons less than smaller ones, outer electrons further away from nucleus

Question 3

what is the trend in oxidising ability?

Answer 3

increases going up the group

Question 4

how are halogens involved in displacement reations

Answer 4

they become oxidising agents ,and a halogen will displace a halide from the solution

Question 5

what element has the highest reducing ability

Answer 5

i-

Question 6

why is chlorine used in water treatment

Answer 6

prevents life threatening diseases by killing bacteria by oxidation

Question 7

how does chlorine react with alkali

Answer 7

reacts with cold dilute sodium hydroxide to form sodium chlorate-forms bleach

Question 8

What is the formula for Chlorine (CL) reacting with potassium bromide solution

Answer 8

Cl2+2kBr–>2KCl(aq)+Br2(aq)

Question 9

What are halides and names

Answer 9

Halides are the 1- ions formed by halogens and end in ide

Question 10

What is the reaction between sodium hydroxide and chlorine(bleach)

Answer 10

2naoh+Cl2–>NaClO+NaCl+H20

Question 11

What is the formula for chlorine and water

Answer 11

cl2+h20=HClO+HCl

Question 12

How do u test for halides using silver nitrate test

Answer 12

• Add dilute nitric acid remove ions
• add silver nitrate=precipitate
• add amonnia distinguish halides

Question 13

How do u test for positive ions in flame test

Answer 13

Dip wire in hcl to clean it and then dip it in unknown compound ,hold the loop in. The blue flame and observe the colour change

Question 14

How do you test for ammonium ions

Answer 14

Damp litmus paper so ammonia gas can dissolve ,if present the paper will turn blue, adding hydroxide ions cause ammonia to react to form NH+h20

Question 15

How do you test for hydroxide ions

Answer 15

Add a PH indicator

Question 16

How do you test for halide ions

Answer 16

Add dilute nitric acid followed by silver nitrate and then add ammonia solution to tell them apart ,silver chlride will dissolve in dilute ammonia solution silver bromide will only dissolve in concentrated ,iodide won’t at all

Question 17

Test for carbonate ions

Answer 17

Adding an acid and it should fiz and test for carbon dioxide using like water and should go cloudy

Question 18

how do halides react with sulfuric acid

Answer 18

NaX+h2so4->nahso4+HX

forms a hydrogen halide

Question 19

How do you test for sulphate ions

Answer 19

using barium chloride. If barium chloride solution is added to a sample of water containing sulfate ions, barium sulfate is formed. Barium sulfate is insoluble in water, and will be seen as a white precipitate.