In the extraction of chlorine by electrolysis of brine ........... .
When copper ore is mixed with silica, in a reverberatory furnace copper matte is produced. The copper matte contains
Which of the following reactions is an example of autoreduction?
A number of elements are available in earth's crust but most abundant elements are ............. .
Zone refining is based on the principle that ............ .
In the extraction of copper from its sulphide ore, the metal is formed by the reduction of $\mathrm{Cu}_2 \mathrm{O}$ with
Brine is electrolysed by using inert electrodes. The reaction at anode is ............... .
In the metallurgy of aluminium ............. .
Electrolytic refining is used to purify which of the following metals?
Extraction of gold and silver involves leaching the metal with $\mathrm{CN}^{-}$ion The metal is recovered by ........... .
Choose the correct option of temperature at which carbon reduces Fe 0 to iron and produces CO.
Below point 'A' Fe0 can ............ .
For the reduction of FeO at the temperature corresponding to point D , which of the following statements is correct?
Match the items of Column I with items of Column II and assign the correct code.
| Column I | Column II | ||
|---|---|---|---|
| A. | Pendulum | 1. | Chrome steel |
| B. | Malachite | 2. | Nickel steel |
| C. | Calamine | 3. | $\mathrm{Na_3AlF_6}$ |
| D. | Cryolite | 4. | $\mathrm{CuCO_3.Cu(OH)_2}$ |
| 5. | $\mathrm{ZnCO_3}$ |
Match the items of Column I with the items of Column II and assign the correct code.
| Column I | Column II | ||
|---|---|---|---|
| A. | Coloured bands | 1. | Zone refining |
| B. | Impure metal to volatile complex | 2. | Fractional distillation |
| C. | Purification of Ge and Si | 3. | Mond's process |
| D. | Purification of mercury | 4. | Chromatography |
| 5. | Liquation |
Match items of Column I with the items of Column II and assign the correct code.
| Column I | Column II | ||
|---|---|---|---|
| A. | Cyanide process | 1. | Ultrapure Ge |
| B. | Froth floatation process | 2. | Dressing of ZnS |
| C. | Electrolytic reduction | 3. | Extraction of Al |
| D. | Zone refining | 4. | Extraction of Au |
| 5. | Purification of Ni |
Match the items of Column I with the items of Column II nd assign the correct code.
| Column I | Column II | ||
|---|---|---|---|
| A. | Sapphire | 1. | $\mathrm{Al_2O_3}$ |
| B. | Sphalerite | 2. | $\mathrm{NaCN}$ |
| C. | Depressant | 3. | $\mathrm{Co}$ |
| D. | Corundum | 4. | $\mathrm{ZnS}$ |
| 5. | $\mathrm{Fe_2O_3}$ |
Match the items of Column I with items of Column II and assign the correct code.
| Column I | Column II | ||
|---|---|---|---|
| A. | Blisterred Cu | 1. | Aluminium |
| B. | Blast furnace | 2. | $\mathrm{2Cu_2O+Cu_2S\longrightarrow 6Cu+SO_2}$ |
| C. | Reverberatory furnace | 3. | Iron |
| D. | Hall-Heroult process | 4. | $\mathrm{FeO+SiO_2\longrightarrow FeSiO_3}$ |
| 5. | $\mathrm{2Cu_2S+3O_2\longrightarrow 2Cu_2O+2SO_2}$ |
Assertion (A) Nickel can be purified by Mond's process.
Reason (R) $\mathrm{Ni}(\mathrm{CO})_4$ is a volatile compound which decomposes at 460 K to give pure Ni.
Assertion (A) Zirconium can be purified by van Arkel method.
Reason (R) $\mathrm{ZrI}_4$ is volatile and decomposes at 1800 K .
Assertion (A) Sulphide ores are concentrated by froth flotation method.
Reason (R) Cresols stabilise the froth in froth floatation method.
Assertion (A) Zone refining method is very useful for producing semiconductors.
Reason (R) Semiconductors are of high purity.
Assertion (A) Hydrometallurgy involves dissolving the ore in a suitable reagent followed by precipitation by a more electropositive metal.
Reason (R) Copper is extracted by hydrometallurgy.
At the temperature corresponding to which of the points in Fig. FeO will be reduced to Fe by coupling the reaction $2 \mathrm{FeO} \longrightarrow \mathrm{WFe}+\mathrm{O}_2$ with all of the following reactions?
$$\text { 1. } \mathrm{C}+\mathrm{O} \longrightarrow \mathrm{CO}_2$$
$$\begin{aligned} & \text { 2. } 2 \mathrm{C}+\mathrm{O}_2 \longrightarrow 2 \mathrm{CO} \\ & \text { 3. } 2 \mathrm{CO}+\mathrm{O}_2 \longrightarrow 2 \mathrm{CO}_2 \end{aligned}$$
Which of the following options are correct?
In the extraction of aluminium by Hall-Heroult process, purified $\mathrm{Al}_2 \mathrm{O}_3$ is mixed with $\mathrm{CaF}_2$ to
Which of the following statements is correct about the role of substances added in the froth floatation process?
In the froth floatation process, zinc sulphide and lead sulphide can be separated by ............ .
Common impurities present in bauxite are ............. .
Which of the following ores are concentrated by froth floatation?
Which of the following reactions occur during calcination?
For the metallurgical process of which of the ores calcined ore can be reduced by carbon?
The main reactions occurring in blast furnace during extraction of iron from haematite ore ............. .
In which of the following method of purification, metal is converted to its volatile compound which is decomposed to give pure metal?
Which of the following statements are correct?
In the extraction of chlorine from brine ........... .
Why is an external emf of more than 2.2 V required for the extraction of $\mathrm{Cl}_2$ from brine?
At temperature above 1073 K, coke can be used to reduce Fe 0 to Fe . How can you justify this reduction with Ellingham diagram?
Wrought iron is the purest form of iron. Write a reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron?
How is copper extracted from low grade copper ores?
Write two basic requirements for refining of a metal by Mond's process and by van Arkel Method.
Although carbon and hydrogen are better reducing agents but they are not used to reduce metallic oxides at high temperatures. Why?
How do we separate two sulphide ores by froth floatation method? Explain with an example.
The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace? Explain by giving reaction.
The mixture of compounds A and B is passed through a column of $\mathrm{Al}_2 \mathrm{O}_3$ by using alcohol as eluant. Compound A is eluted in preference to compound B . Which of the compounds A or B, is more readily adsorbed on the column?
Why is sulphide ore of copper heated in a furnace after mixing with silica?
Why are sulphide ores converted to oxide before reduction?
Which method is used for refining Zr and Ti ? Explain with equation.
What should be the considerations during the extraction of metals by electrochemical method?
What is the role of flux in metallurgical processes?
How are metals used as semiconductors refined? What is the principle of the method used like germanium, silicon etc?
Write down the reactions taking place in blast furnace related to the metallurgy of iron in the temperature range 500-800 K.
Give two requirements for vapour phase refining.
Write the chemical reactions involved in the extraction of gold by cyanide process. Also give the role of zinc in the extraction.
Explain the following
(a) $\mathrm{CO}_2$ is a better reducing agent below 710 K whereas CO is a better reducing agent above 710 K.
(b) Generally sulphide ores are converted into oxides before reduction.
(c) Silica is added to the sulphide ore of copper in the reverberatory furnace.
(d) Carbon and hydrogen are not used as reducing agents at high temperatures.
(e) Vapour phase refining method is used for the purification of Ti .