Which series of reactions correctly represent chemical relations related to iron and its compound
This problem involves the concept of Ellingham diagramas this diagram predicts the basis of oxidation state and stability of iron compounds.
The above given reaction series is incorrect. The correct reactions series is as follows :
This reaction series is also incorrect. The correct reaction series is
The reaction of FeCI3 is not possible. Thus, the above reaction series is incorrect.
This reaction series is correct.
Which method of purification is represented by the following equation?
van-Arkel method is used for refining titanium and zirconium. This method is use ful for removing volatile impurities Iike O2, N2, I2 present in the metals of Zr and Ti.
In this method, metal iodide is formed by direct combination of metal and iodine.
The metal iodide undergo decomposition on a tungsten filament and thus, pure metal is deposited on the filament.
Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly?
The value of ΔG for the formation of CO2 is negative , i.e. it is thermodynamically more stable than CS2. Also, metal sulphides are thermodynamically more stable than CS2.
Metal sulphides are more stable than the corresponding oxides, so they are roasted to convert into less stable oxides.
During the process of electrolytic refining of copper, some metals present as impurity settle as anodemud. These are
During electrolysis, noble metals (inert metals) like Ag , Au and Pt are not affected and separate as anode mud from the impure anode.
Which one of the following ores is best concentrated by froth floatation method ?
Froth floatation is used to concentrate sulphide ores (Galena (PbS)].
Aluminium is extracted by the electrolysis of
Aluminium is extracted by electrolysis of a fused mixture of alumina (2-8%), synthetic cryolite Na3 AIF6 (80-85%), AIF3 and fluorspar. This makes alumina good conductor and lowers the fusion temperature also.
Cyanide process is used for the extraction of
Cyanide process or Mac Arthur-Forest cyanide process
2Ag2S + 8NaCN + O2 + 2H2O → 4Na[Ag(CN)2] + 4NaOH + 2S
Soluble silver complex is filtered and treated with zinc dust and silver gets precipitated.
Refining of impure copper with zinc impurity is to be done by electrolysis using electrodes as
For purification, impurities like Se, Te, Ag, Au gets oxidised (deelectronation) falling into solution near anode and settle as anode mud.