Chemistry
Get insights from 6.9k questions on Chemistry, answered by students, alumni, and experts. You may also ask and answer any question you like about Chemistry
Follow Ask QuestionQuestions
Discussions
Active Users
Followers
New answer posted
a year agoContributor-Level 10
13. Vapor phase refining or Van Arkel's method is used for refining Zr and Ti.
Vapor refining or vapor phase process: The metal is collected in the form of volatile compound that decomposes to pure metal.
Van Arkel method: This method is useful for removing all Oxygen and nitrogen present in the form of impurity in metals like Zr and Ti. The crude metal is heated in an empty vessel with a small amount of iodine. The metal iodine being more covalent volatilises. Impure Zr reacts with iodine to form zirconium tera iodide.
The following reaction occurs Zr + 2I2? ZrI4 The metal iodide is decomposed on
New answer posted
a year agoContributor-Level 10
33. Option (ii) neutral is correct since p-type semiconductor mainly contains positively charged carriers ( holes ) which are able to move freely. It is still considered to be neutral as the fixed acceptor atoms having accepted electrons are negative.
New answer posted
a year agoContributor-Level 10
12. Sulfide ore of copper contains some types of impurities. Sulfide ores are not reduced easily, but oxide ores are easily reduced. It is necessary to make sulfide ores free from volatile impurities. This can be performed by a roasting method. In this moisture escape and impurities like sulfur, phosphorus, arsenic are oxidized to their volatile oxides. It is performed in a reverberatory furnace. After this process the mass becomes porous.
New answer posted
a year agoContributor-Level 10
32. Option (ii) equal number of cations and anions are missing from the lattice is correct since Schottky defect in crystals occurs when equal numbers of cations and anions are missing from the lattice.
New answer posted
a year agoContributor-Level 10
10. Sulfide ores are not reduced easily, but oxide ores are easily reduced. Sulfide ore of copper contains some types of impurities. This can cause by-product formation and degrade our final product. Iron oxide is present as a key impurity of concern in sulfide ore of copper. During the roasting process the temperature in the furnace is near about 1200°C. During such high temperatures iron oxide which is gangue (impurity) in ore forms slag. Slag is insoluble in molten metal and being lighter floats over the surface of molten metal. Here silica is used as flux.
FeO + SiO2 →FeSiO3
New answer posted
a year agoContributor-Level 10
31. Option (i) Frenkel defect is correct since it is a type of defect in which an atom is dislocated from its lattice position to an interstitial site.
New answer posted
a year agoContributor-Level 10
30. Option (iv) ionic solid is correct since in graphite each atom is linked to the other through a covalent bond and hence it is a covalent solid and cannot fall under the category of ionic solid.
New answer posted
a year agoContributor-Level 10
29. Option (iii) electron is correct since lattice sites can only be occupied by electrons when there is imperfection in a solid and do not occur in pure crystals. Hence, the lattice site in a pure crystal cannot be occupied by electrons.
New answer posted
a year agoContributor-Level 10
28. Option (iv) CrO2 is correct since it shows electrical conductivity similar to the metals.
New answer posted
a year agoContributor-Level 10
27. Option (iii) TiO3 is correct since certain metal oxides such as VO, VO2, VO3and TiO3 show either metallic or insulating properties depending upon the temperature.
Taking an Exam? Selecting a College?
Get authentic answers from experts, students and alumni that you won't find anywhere else
Sign Up on ShikshaOn Shiksha, get access to
- 66k Colleges
- 1.2k Exams
- 703k Reviews
- 1850k Answers