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(c) (ii) (I) Why highly reactive metals cannot be obtained from their oxides by using carbon as a reducing agent ?
(II) Why solder, an alloy of lead and tin, is used for welding electrical wires together ?
(II) Why solder, an alloy of lead and tin, is used for welding electrical wires together ?
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(a) Because it is easier to obtain metal from its oxide. /
Because it is easier to reduce metal oxide to metal (1)
(b)
$\ce{Fe2O3(s)+ 2Al(s) -> 2Fe(l) + Al2O3(s) + Heat}$
$\ce{3MnO2(s) + 4Al(s) -> 3Mn(l) + 2Al2O3(s) + Heat}$ (1)
(balancing is optional) (any one equation)
(c) (i) $\ce{2Cu2S + 3O2(g) ->[Heat] 2Cu2O(s) + 2SO2 (g)}$ (1)
$\ce{2Cu2O + Cu2S ->[Heat] 6Cu(s) + SO2(g)}$ (1)
OR
(c)(ii) (I) Because highly reactive metals have more affinity for
oxygen than carbon. (1)
(II) Because of its low melting point. (1)
Because it is easier to reduce metal oxide to metal (1)
(b)
$\ce{Fe2O3(s)+ 2Al(s) -> 2Fe(l) + Al2O3(s) + Heat}$
$\ce{3MnO2(s) + 4Al(s) -> 3Mn(l) + 2Al2O3(s) + Heat}$ (1)
(balancing is optional) (any one equation)
(c) (i) $\ce{2Cu2S + 3O2(g) ->[Heat] 2Cu2O(s) + 2SO2 (g)}$ (1)
$\ce{2Cu2O + Cu2S ->[Heat] 6Cu(s) + SO2(g)}$ (1)
OR
(c)(ii) (I) Because highly reactive metals have more affinity for
oxygen than carbon. (1)
(II) Because of its low melting point. (1)