The term “Chromatography” means -
1. Technique for the preparation of mixtures.
2. Technique for the separation of mixtures.
3. Technique for the separation of ore.
4. Technique for the preparation of aluminium.
Which of the following statements is true about the refining of nickel?
1. | Nickel is heated in the presence of NO2 to form nickel tetracarbonyl. |
2. | Nickel is heated in the presence of CO to form nickel tetracarbonyl. |
3. | Nickel is heated in the presence of CO2 to form nickel tetracarbonyl. |
4. | Nickel is heated in the presence of SO2 to form nickel tetracarbonyl. |
‘Cast iron’ is different from ‘Pig iron' because :
1. | Cast iron is obtained by melting pig iron and coke using a hot air blast. |
2. | Cast iron contains lower amount of carbon (3%) than pig iron. |
3. | Unlike pig iron, cast iron is extremely hard and brittle. |
4. | All of the above |
The correct statement among the following is:
1. | All ores are minerals, but all minerals are not necessarily ores. |
2. | Minerals are an economical source of metal |
3. | Extraction of metal from ores is difficult. |
4. | None of the above |
Copper matte is put in silica lined converter to :
1. | Remove the remaining H2SO4 and H2S present in the matte as slag. |
2. | Remove the remaining MnO and FeS present in the matte as slag. |
3. | Remove the remaining Fe2O3 and Fe2S present in the matte as slag. |
4. | Remove the remaining FeO and FeS present in the matte as slag. |
The role of cryolite in the metallurgy of aluminium is :
1. | To decrease the melting point of the mixture from 2323 K to 1140 K |
2. | To increase the electrical conductivity of |
3. | To decrease the electrical conductivity of |
4. | Both '1' and '2' |
Leaching of low-grade copper ores does not involve
1. Cu getting converted into Cu2+(aq) in acidic medium
2. Cu getting converted into Cu2+(aq) in basic medium
3. Cu2+(aq) getting reduced to Cu
4. using bacteria in the presence of air.
Zinc cannot be extracted from zinc oxide via CO reduction because:
(Given: Ellingham diagram)
1. | \(\Delta G_{f}^{o} \) of Zn from ZnO is lower than that of CO2 from CO |
2. | \(\Delta G_{f}^{o} \) of ZnO from Zn is lower than that of CO2 from CO |
3. | ZnO is less stable than CO |
4. | ZnO is more stable than CO |
The value of ∆fGO for the formation of is – 540 kJmol−1and that of Al2O3 is – 827 kJ mol−1. The correct statement is-
1. Cr can reduce Al2O3 to Al
2. Cr2O3 cannot reduce Al2O3 to Al
3. Al can reduce to Cr
4. Al cannot reduce to Cr
The better reducing agent for ZnO is:
1. C
2. CO
3. CO2
4.