Other Reactions of Halides

Question 1

what is the reagent in testing for halide ions in solutions and why

Answer 1

• silver nitrate solution

- because silver halides are insoluble in water

Question 2

what is added before the silver nitrate solution for safe measure

Answer 2

• dilute nitric acid

Question 3

why is dilute nitric acid added

Answer 3

• to make sure other anions like carbonate ions are removed

- as they would also form precipitates

Question 4

why would add ammonia solution after you have added the halogen and formed a precipitate

Answer 4

• to further test the halides

- this would be dependent on whether the halide ions become soluble or not when ammonia is added

Question 5

what are the effects of adding dilute aqueous ammonia to the ions of the main 3 halogens

Answer 5

• chloride ions = soluble
• bromide ions = insoluble
• iodide ions = insoluble

Question 6

what are the effects of adding concentrated aqueous ammonia to the ions of the main 3 halogens

Answer 6

• chloride ions = soluble
• bromide ions = soluble
• iodide ions = insoluble

Question 7

why cant this test be used for fluoride ions

Answer 7

• because silver fluoride is soluble in water

Question 8

what are the colours of the precipitates formed by silver chloride bromide and iodide

Answer 8

• silver chloride = white
• silver bromide = cream
• silver iodide = yellow

Question 9

what is the general ionic equation for the formation of the precipitate

Answer 9

Ag+(aq) + X-(aq) = AgX(s)

Question 10

why do silver chloride and bromide become soluble when concentrated aqueous ammonia is added to them

Answer 10

they get dissolved due to the formation of a complex ion

Question 11

what would be the equation for the reaction between silver chloride and aqueous ammonia

Answer 11

AgCl(s) + 2NH3(aq) = [Ag(NH3)2]+(aq) + Cl-(aq)

Question 12

what do all the hydrogen halides have in common

Answer 12

• they are colourless gases

- they exist as polar diatomic molecules

Question 13

what does the reaction between hydrogen halides and water form

Answer 13

acidic solutions that are colourless

Question 14

what is the general equation for this reaction

Answer 14

HX + H2O = H3O+ + X-

Question 15

what is the general name for the acid formed

Answer 15

• hydrohalic acid

- for iodine its hydriodic acid

Question 16

what does the reaction between hydrogen halides and ammonia gas form

Answer 16

• salts

- all of which are white ionic solids

Question 17

what is the equation for the reaction between hydrogen chloride and ammonia

Answer 17

NH3(g) + HCl(g) = NH4Cl(s)