189674
In the extraction of aluminium the electrolyte is
1 Fused cryolite with felspar
2 Fused cryolite with fluorspar
3 Pure alumina in molten cryolite
4 Pure alumina with bauxite and molten cryolite
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189675
Aluminium is obtained by
1 Reducing \(A{l_2}{O_3}\) with coke
2 Electrolysing \(A{l_2}{O_3}\) dissolved in \(N{a_3}Al{F_6}\)
3 Reducing \(A{l_2}{O_3}\) with chromium
4 Heating alumina and cryolite
Explanation:
Aluminium is obtained by electrolising alumina dissolved in cryolite \(\left( Na _3 AlF _6\right)\) \(4 Na _3 AlF _6 \leftrightharpoons 12 Na ^{+}+4 Al ^{3+}+12 F ^{-}\) \(4 Al ^{3+}+12 e ^{-} \rightarrow 4 Al \text { (at cathode) }\) \(12 F ^{-} \rightarrow 6 F _2+12 e ^{-} \text {(at anode) }\) \(2 Al _2 O _3+6 F _2 \rightarrow AlF _3+3 O _2\)
11. THE P-BLOCK ELEMENTS
189676
In the electrolysis of alumina, cryolite is added to
1 Increase the melting point of alumina
2 Increase the electrical conductivity
3 Minimise the anodic effect
4 Remove impurities from alumina
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189677
The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite \((N{a_3}Al{F_6})\) is
1 As a catalyst
2 To lower the temperature of the melt and to make the fused mixture very conducting
3 To decrease the rate of oxidation of carbon at the anode
4 None of the above
Explanation:
Fluorspar \(( CaF_2 )\) is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite \(( Na_3A l F_6)\). Addition of cryolite and fluorspar increases the electrical conductivity of alumina and lowers the fusion temperature to around \(1140 \,K\).
11. THE P-BLOCK ELEMENTS
189678
For purification of alumina, the modern processes most useful when \((i)\) the impurity present is a lot of iron oxides and \((ii)\) the impurity present is a lot of silica, are
1 For \((i)\) Hall's process; for \((ii)\) Baeyer's process
2 For \((i)\) Hall's process; for \((ii)\) Serpeck's process
3 For \((i)\) Serpeck's process; for \((ii)\) Baeyer's process
4 For \((i)\) Baeyer's process; for \((ii)\) Serpeck's process
Explanation:
(d) Iron oxide impurity -Baeyer’s process Silica impurity -Serpeck’s process
189674
In the extraction of aluminium the electrolyte is
1 Fused cryolite with felspar
2 Fused cryolite with fluorspar
3 Pure alumina in molten cryolite
4 Pure alumina with bauxite and molten cryolite
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189675
Aluminium is obtained by
1 Reducing \(A{l_2}{O_3}\) with coke
2 Electrolysing \(A{l_2}{O_3}\) dissolved in \(N{a_3}Al{F_6}\)
3 Reducing \(A{l_2}{O_3}\) with chromium
4 Heating alumina and cryolite
Explanation:
Aluminium is obtained by electrolising alumina dissolved in cryolite \(\left( Na _3 AlF _6\right)\) \(4 Na _3 AlF _6 \leftrightharpoons 12 Na ^{+}+4 Al ^{3+}+12 F ^{-}\) \(4 Al ^{3+}+12 e ^{-} \rightarrow 4 Al \text { (at cathode) }\) \(12 F ^{-} \rightarrow 6 F _2+12 e ^{-} \text {(at anode) }\) \(2 Al _2 O _3+6 F _2 \rightarrow AlF _3+3 O _2\)
11. THE P-BLOCK ELEMENTS
189676
In the electrolysis of alumina, cryolite is added to
1 Increase the melting point of alumina
2 Increase the electrical conductivity
3 Minimise the anodic effect
4 Remove impurities from alumina
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189677
The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite \((N{a_3}Al{F_6})\) is
1 As a catalyst
2 To lower the temperature of the melt and to make the fused mixture very conducting
3 To decrease the rate of oxidation of carbon at the anode
4 None of the above
Explanation:
Fluorspar \(( CaF_2 )\) is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite \(( Na_3A l F_6)\). Addition of cryolite and fluorspar increases the electrical conductivity of alumina and lowers the fusion temperature to around \(1140 \,K\).
11. THE P-BLOCK ELEMENTS
189678
For purification of alumina, the modern processes most useful when \((i)\) the impurity present is a lot of iron oxides and \((ii)\) the impurity present is a lot of silica, are
1 For \((i)\) Hall's process; for \((ii)\) Baeyer's process
2 For \((i)\) Hall's process; for \((ii)\) Serpeck's process
3 For \((i)\) Serpeck's process; for \((ii)\) Baeyer's process
4 For \((i)\) Baeyer's process; for \((ii)\) Serpeck's process
Explanation:
(d) Iron oxide impurity -Baeyer’s process Silica impurity -Serpeck’s process
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11. THE P-BLOCK ELEMENTS
189674
In the extraction of aluminium the electrolyte is
1 Fused cryolite with felspar
2 Fused cryolite with fluorspar
3 Pure alumina in molten cryolite
4 Pure alumina with bauxite and molten cryolite
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189675
Aluminium is obtained by
1 Reducing \(A{l_2}{O_3}\) with coke
2 Electrolysing \(A{l_2}{O_3}\) dissolved in \(N{a_3}Al{F_6}\)
3 Reducing \(A{l_2}{O_3}\) with chromium
4 Heating alumina and cryolite
Explanation:
Aluminium is obtained by electrolising alumina dissolved in cryolite \(\left( Na _3 AlF _6\right)\) \(4 Na _3 AlF _6 \leftrightharpoons 12 Na ^{+}+4 Al ^{3+}+12 F ^{-}\) \(4 Al ^{3+}+12 e ^{-} \rightarrow 4 Al \text { (at cathode) }\) \(12 F ^{-} \rightarrow 6 F _2+12 e ^{-} \text {(at anode) }\) \(2 Al _2 O _3+6 F _2 \rightarrow AlF _3+3 O _2\)
11. THE P-BLOCK ELEMENTS
189676
In the electrolysis of alumina, cryolite is added to
1 Increase the melting point of alumina
2 Increase the electrical conductivity
3 Minimise the anodic effect
4 Remove impurities from alumina
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189677
The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite \((N{a_3}Al{F_6})\) is
1 As a catalyst
2 To lower the temperature of the melt and to make the fused mixture very conducting
3 To decrease the rate of oxidation of carbon at the anode
4 None of the above
Explanation:
Fluorspar \(( CaF_2 )\) is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite \(( Na_3A l F_6)\). Addition of cryolite and fluorspar increases the electrical conductivity of alumina and lowers the fusion temperature to around \(1140 \,K\).
11. THE P-BLOCK ELEMENTS
189678
For purification of alumina, the modern processes most useful when \((i)\) the impurity present is a lot of iron oxides and \((ii)\) the impurity present is a lot of silica, are
1 For \((i)\) Hall's process; for \((ii)\) Baeyer's process
2 For \((i)\) Hall's process; for \((ii)\) Serpeck's process
3 For \((i)\) Serpeck's process; for \((ii)\) Baeyer's process
4 For \((i)\) Baeyer's process; for \((ii)\) Serpeck's process
Explanation:
(d) Iron oxide impurity -Baeyer’s process Silica impurity -Serpeck’s process
189674
In the extraction of aluminium the electrolyte is
1 Fused cryolite with felspar
2 Fused cryolite with fluorspar
3 Pure alumina in molten cryolite
4 Pure alumina with bauxite and molten cryolite
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189675
Aluminium is obtained by
1 Reducing \(A{l_2}{O_3}\) with coke
2 Electrolysing \(A{l_2}{O_3}\) dissolved in \(N{a_3}Al{F_6}\)
3 Reducing \(A{l_2}{O_3}\) with chromium
4 Heating alumina and cryolite
Explanation:
Aluminium is obtained by electrolising alumina dissolved in cryolite \(\left( Na _3 AlF _6\right)\) \(4 Na _3 AlF _6 \leftrightharpoons 12 Na ^{+}+4 Al ^{3+}+12 F ^{-}\) \(4 Al ^{3+}+12 e ^{-} \rightarrow 4 Al \text { (at cathode) }\) \(12 F ^{-} \rightarrow 6 F _2+12 e ^{-} \text {(at anode) }\) \(2 Al _2 O _3+6 F _2 \rightarrow AlF _3+3 O _2\)
11. THE P-BLOCK ELEMENTS
189676
In the electrolysis of alumina, cryolite is added to
1 Increase the melting point of alumina
2 Increase the electrical conductivity
3 Minimise the anodic effect
4 Remove impurities from alumina
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189677
The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite \((N{a_3}Al{F_6})\) is
1 As a catalyst
2 To lower the temperature of the melt and to make the fused mixture very conducting
3 To decrease the rate of oxidation of carbon at the anode
4 None of the above
Explanation:
Fluorspar \(( CaF_2 )\) is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite \(( Na_3A l F_6)\). Addition of cryolite and fluorspar increases the electrical conductivity of alumina and lowers the fusion temperature to around \(1140 \,K\).
11. THE P-BLOCK ELEMENTS
189678
For purification of alumina, the modern processes most useful when \((i)\) the impurity present is a lot of iron oxides and \((ii)\) the impurity present is a lot of silica, are
1 For \((i)\) Hall's process; for \((ii)\) Baeyer's process
2 For \((i)\) Hall's process; for \((ii)\) Serpeck's process
3 For \((i)\) Serpeck's process; for \((ii)\) Baeyer's process
4 For \((i)\) Baeyer's process; for \((ii)\) Serpeck's process
Explanation:
(d) Iron oxide impurity -Baeyer’s process Silica impurity -Serpeck’s process
189674
In the extraction of aluminium the electrolyte is
1 Fused cryolite with felspar
2 Fused cryolite with fluorspar
3 Pure alumina in molten cryolite
4 Pure alumina with bauxite and molten cryolite
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189675
Aluminium is obtained by
1 Reducing \(A{l_2}{O_3}\) with coke
2 Electrolysing \(A{l_2}{O_3}\) dissolved in \(N{a_3}Al{F_6}\)
3 Reducing \(A{l_2}{O_3}\) with chromium
4 Heating alumina and cryolite
Explanation:
Aluminium is obtained by electrolising alumina dissolved in cryolite \(\left( Na _3 AlF _6\right)\) \(4 Na _3 AlF _6 \leftrightharpoons 12 Na ^{+}+4 Al ^{3+}+12 F ^{-}\) \(4 Al ^{3+}+12 e ^{-} \rightarrow 4 Al \text { (at cathode) }\) \(12 F ^{-} \rightarrow 6 F _2+12 e ^{-} \text {(at anode) }\) \(2 Al _2 O _3+6 F _2 \rightarrow AlF _3+3 O _2\)
11. THE P-BLOCK ELEMENTS
189676
In the electrolysis of alumina, cryolite is added to
1 Increase the melting point of alumina
2 Increase the electrical conductivity
3 Minimise the anodic effect
4 Remove impurities from alumina
Explanation:
It’s Obvious.
11. THE P-BLOCK ELEMENTS
189677
The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite \((N{a_3}Al{F_6})\) is
1 As a catalyst
2 To lower the temperature of the melt and to make the fused mixture very conducting
3 To decrease the rate of oxidation of carbon at the anode
4 None of the above
Explanation:
Fluorspar \(( CaF_2 )\) is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite \(( Na_3A l F_6)\). Addition of cryolite and fluorspar increases the electrical conductivity of alumina and lowers the fusion temperature to around \(1140 \,K\).
11. THE P-BLOCK ELEMENTS
189678
For purification of alumina, the modern processes most useful when \((i)\) the impurity present is a lot of iron oxides and \((ii)\) the impurity present is a lot of silica, are
1 For \((i)\) Hall's process; for \((ii)\) Baeyer's process
2 For \((i)\) Hall's process; for \((ii)\) Serpeck's process
3 For \((i)\) Serpeck's process; for \((ii)\) Baeyer's process
4 For \((i)\) Baeyer's process; for \((ii)\) Serpeck's process
Explanation:
(d) Iron oxide impurity -Baeyer’s process Silica impurity -Serpeck’s process