Page 259 - Chemistry

Chloride gas is produce
-
2Cl (aq) Cl 2(g) + 2e -

-
50. a) C10 3 (=) Cl + 3(-2) = -1(=)Cl -6 =-1,Cl= + 5

+5 0
+
-
-
C10 3 (aq) 6H (aq)+5e Cl 2(g)+ 3H 2O (l)

-
b) NO 2 (=) N+2 (-2) = -1(=) N-4 = -1 (=) = N+ 3

+3 +5
-
-
+
-
NO 2 +H 2O (l) NO 3(aq)+2H (aq) + 2e

51.


Half Cell E / V E / V using iron ref - electrode
Al (s) /Al 3+ (aq) - 1.66 - 1.22
Zw (s) / Zn 2+ (aq) - 0.76 +0.32
Fe (s)/Fe 2+ (aq) - 0.44 0.00
Ni (s) /Ni 2+ (aq) - 0.25 + 0.19

52.  = 1.5 X 60 X 15 = 1350
-
J 3+ (aq) + 3e J (s)
3F = 3 X 96500 = 289 500C
289500C deposit = 52g of J (s)
= 1350 C deposit = 1350 X 52
289500 = 0.2 2425g

53. Tin (Sn) its oxidation potential is +0.144V. It is the least likely to combine/ react with elements
of weather

5. Metals
1. a) chlorine gas would react with steel anode

24
b) Hood and steel gauze prevent chlorine sodium, from anode and cathode from mixing

Na
11
and reacting. Na

- Sodium metal is less dense, floats on motten brine where it is siphoned out.
c) -To Whom It May Concern: melt the ore, rock salt
- For electrolysis of the molten ore
2. a) SO 2(g) is produced as a by- product, this mixes with rain water producing acid rain which
may corrode buildings and affect plants  ½
SO 2(g) is poisonous when inhaled  ½
b) - H 2SO 4 manufacture – to make use of SO 2 (g)
- Manufacture of dry cells – make use of zinc
- Production of iron sheets which are galvanized using zinc (Any one with an explanation)
c) Low density, does not corrode easily, duchle, malleable (Any 2 each ½ mark)
3. Aluminium is lighter/low density. (any)
 1
It is a good conductor of electricity
4. Stage 1 – oxidation; Coke is oxidized to CO  ½
Stage 2 – Reduction: zinc is reduced to Zinc metal
 ½
 ½
 ½
Stage 3;- Recycling stage; CO 2 is reduced to regenerate CO

1
√
5. a) Q is sulphur (IV) oxide SO 2(g).
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