Question | Answer |
Describe the trend in Atomic Radii of The Halogens: | Going down the group, the Atomic Radii increases as electrons are in higher energy shells, have more electron shield so the attraction to the nucleus is decreased. |
Describe the Trend in Electronegativity of the Halogens: | Halogens increase in Electronegativity going up the group with F being the most. |
Describe the trends in MP and BP of the Halogens: | The BP and MP of the Halogens increases going down the group, this is because there are more electrons and a larger mass in the molecules, so the van der Waals forces increase. |
Describe the trend in Oxidation ability of the Halogens: | The more electronegative, the stronger the Oxidiser. |
Describe the trend in Reducing power of the Halide Ions: | Reducing power increases going down the group of Halogens when they are in Ion form. F- being the weakest and I- the strongest. |
What is the name of the type of reaction when Cl- is removed by Fl2? | A Displacement Reaction. |
What would happen and what would be seen if NaBr was reacted with Cl2? | Cl would displace the Br and form NaCl, Bromine PP would become visible. |
What is seen when NaCl is reacted with Concentrated H2SO4? | Steamy fumes of HCl are produced and a Solid NaHSO4 is produced. |
What is seen whe NaBr is reacted with Conc H2SO4? | Steamy HBr is produced, along with NaHSO4, Bromine PP and Sulfur is reduced to SO4 (+4). Also water is produced. |
What is seeen when NaI reacts with H2SO4? | HI gas is produced, Iodine Solid is produced, Sulfur is reduced to H2S (+2) which has an egg smell, Water is produced and so is NaHSO4. |
Which has the strongest reducing power, NaCL, NaBr or NaI? | NaI, as the Iodine Ion is the largest and can lose its electron the easiest. |
What is the test to see which Halide Ion is present in a Solution? | Treat with dilute HNO3 (Nitric Acid) and then add Silver Nitrate (AgNO3). Observe what is formed to identify which Halide Ion is present. |
What occurs when reacting NaF with AgNO3? | No PP is formed as Fluorine will dissolve in water. |
What occurs when reacting NaCl with AgNO3? | AgCl will be formed which is a WHITE Precipitate. |
What occurs when reacting NaBr with AgNO3? | AgBr will form which is a CREAM coloured Precipitate. |
What occurs when reacting NaI with AgNO3? | AgI is formed which is a Yellow Precipitate. |
How can you further test, after reacting a Sodium Halide with Silver Nitrate, to see which Halide is present? | When adding ammonia; AgI will not dissolve, AgCl will dissolve quickly, AgBr will dissolve slower than AgCl. |
Why is Nitric Acid added to a Sodium Halide before adding Silver Nitrate? | This is to remove any Carbonate (CO3 2-) ions and OH- Ions. |
Why can't HCl or H2SO4 be added to treat a Sodium Halide before testing with AgNO3? | Because HCl and H2SO4 would both form precipitates. |
What is a Disproprotionation reaction? | A Reaction in which a specific species is oxidised and reduced to form two different products. |
Give an example of a Disproportionation: | Cl2 + H2O <--> ClOH + HCl
(Chlorine + Water ---> Chloric (I) Acid + Hydrochloric Acid) |
Why is Chlorine added to water to make it safer to drink or swim in? | Chloric (I) Acid is an oxidising Agent and is able to kill off Bacteria preventing diseases such as Cholera and Typhoid. |
What is the reaction of water with Chlorine in sunlight? | 2H20 + 2Cl2 <--> 4HCl + O2
Water + Chlorine (+Sunlight) <---> Hydrochloric Acid + Oxygen. |
What is Chlorine's reaction with Alkali? Name an Alkali that it is reacted with. | Cl2 + 2NaOH ---> NaCl + NaClO + H20.
Chlorine + Sodium Hydroxide --> Sodium Chloride + Sodium Chlorate (I) + Water. This is a disproportionation reaction. |
What is the reaction of Chlorine with NaOH useful? | It forms NaClO (Sodium Chlorate (I)) which is an oxidising agent and a component in Bleach. |
What is the name of reaction between Chlorine and Sodium Hydroxide to form NaCl + NaClO + H2O? | |