a. Describe how iron and aluminum reacts with each of the following substances: i. dilute \(H_2SO_4\); ii. dilute \(HNO_3\)
bi. Write an equation for the burning of sulphur in air.
ii. Name the catalyst used in the contact process.
iii. In the contact process, why is an excess of air used?
iv. Why is it necessary to cool the catalyst used in 5(b)(ii)?
v. Give a reason why the air used in the contact process needs to be as clean as possible.
vi. State two reasons why SO2 should not be discharged into the atmosphere.
ci. State the reagents and conditions used in the laboratory preparation of chlorine.
ii. State two uses of chlorine.
di. Name the drying agents for each of the following gases: 1. Hydrogen;
i2. sulphur (IV) oxide;
i3. Ammonia.
ii1. State the components of the following
Bronze; ii2. Brass.
Explanation
ai. Iron dissolves readily in dilute \(H_2SO_4\) liberating hydrogen and forming \(FeSO_4\) while with Aluminum there is no reaction.
ii. With aluminum there is no reaction(1)while iron dissolves in dilute \(HNO_3\) liberating hydrogen and forming \(Fe(NO_3)_2\)
bi. \(S+O_2→SO_2\)
ii. Vanadium(V) oxide/ platinized asbestos.
iii. To favour the formation of more product/\(SO_3\).
iv. The reaction is exothermic/high temperature favours the formation of more reactants/backward reaction.
v. Catalysts are easily poisoned/easily damaged by dirt.
vi. -SO2 damages buildings
-damages living things
-causes acid rain
-irritates eyes, nose and throat
-causes lung and respiratory diseases eg coughing, bronchitis, etc
ci. Reagents
-manganese(IV)oxide/MnO2
-concentrated HCI
Conditions
-heating
Concentrated HCI(1)
Bleaching powder/CaOCl2/KMnO4crystals
Room temperature/heat is not required
ii.
-for bleaching wood pulp and textiles
-for the production of plastics
-for recovering of tin from its ore/extraction of tin
-as a germicide and disinfectant/insecticide/in swimming pools
-to sterilize/purification of water supply
-for commercial manufacture of HCI
-production of dyes and drugs
-manufacture of solvents eg \(CCL_4\), \(CHCI_3\)
di1. Hydrogen-fused calcium chloride/conc.tetraoxosulphate(VI)acid
i2. Sulphur(IV)oxide-concentrated tetraoxosulphate(VI)acid/ anhydrous Calcium chloride
i3. calcium oxide/ quick lime/silica gel
ii1. copper and tin
ii2. Copper and zinc