Chapter 18

Excess of \(\mathrm{KI}\) react with \(\mathrm{CuSO}_{4}\) solution and then \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) solution is added to it. Which of the following statements is incorrect for this reaction? (a) \(\mathrm{Cu}_{2} \mathrm{I}_{2}\) is formed (b) \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) is oxidized (c) \(\mathrm{CuI}_{2}^{2}\) is formed (d) Evolved \(\mathrm{I}_{2}\) is reduced

Among the properties (A) reducing (B) oxidizing (C) complexing, the set of properties shown by \(\mathrm{CN}^{-}\)ion towards metal species is (a) \(\mathrm{A}, \mathrm{B}\) (b) \(\mathrm{B}, \mathrm{C}\) (c) \(\mathrm{C}, \mathrm{A}\) (d) \(\mathrm{A}, \mathrm{B}, \mathrm{C}\)

During the process of electrolytic refining of copper some metals present as impurity settle as anode mud. These are (a) \(\mathrm{Ag}\) and \(\mathrm{Au}\) (b) \(\mathrm{Pb}\) and \(\mathrm{Zn}\) (c) \(\mathrm{Fe}\) and \(\mathrm{Ni}\) (d) \(\mathrm{Sn}\) and \(\mathrm{Ag}\)

Heating mixture of \(\mathrm{Cu}_{2} \mathrm{O}\) and \(\mathrm{Cu}_{2} \mathrm{~S}\) will give (a) \(\mathrm{Cu}+\mathrm{SO}_{2}\) (b) \(\mathrm{Cu}+\mathrm{SO}_{3}\) (c) \(\mathrm{CuO}+\operatorname{CuS}\) (d) \(\mathrm{Cu}_{2} \mathrm{SO}_{3}\)

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? (a) Metal sulphides are thermodynamically more stable than \(\mathrm{CS}_{2}\) (b) \(\mathrm{CO}_{2}\) is thermodynamically more stable than \(\mathrm{CS}_{2}\) (c) Metal sulphides are less stable than the corresponding oxides (d) \(\mathrm{CO}_{2}\) is more volatile than \(\mathrm{CS}_{2}\).

Which method of purification is represented by the following equation: \(\mathrm{Ti}(\mathrm{s})+2 \mathrm{I}_{2}(\mathrm{~g}) \stackrel{\mathrm{S} 23 \mathrm{~K}}{\longrightarrow} \mathrm{Ti} \mathrm{I}_{4}(\mathrm{~g}) \stackrel{1 \pi 0 \mathrm{~K}}{\longrightarrow} \mathrm{Ti}(\mathrm{s})+2 \mathrm{I}_{2}(\mathrm{~g})\) (a) Poling (b) Cupellation (c) Zone refining (d) Van Arkel

Iron exhibits \(+2\) and \(+3\) oxidation states. Which of the following statements about iron is incorrect? (a) Ferrous compounds are less volatile than the corresponding ferric compounds (b) Ferrous compounds are relatively more ionic than the corresponding ferric compounds. (c) Ferrous oxide is more basic in nature than the ferric oxide (d) Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds

In the context of the Hall-Heroult process for the extraction of \(\mathrm{Al}\), which of the following statement is false? (a) \(\mathrm{CO}\) and \(\mathrm{CO}_{2}\) are produced in this process (b) \(\mathrm{Al}_{2} O_{3}\) is mixed with \(\mathrm{CaF}_{2}\) which lowers the melting point of the mixture and brings conductivity (c) \(\mathrm{Al}^{3+}\) is reduced at the cathode to form \(\mathrm{Al}\) (d) \(\mathrm{Na}_{3} \mathrm{~A} / \mathrm{F}_{6}\) serves as the electrolyte

Which of the following are is best concentrated by froth floatation method? (a) Siderite (b) Galena (c) Malachite (d) magnetite

Galvanization is applying a coating of? (a) \(\mathrm{Cu}\) (b) \(\mathrm{Zn}\) (c) \(\mathrm{Cr}\) (d) \(\mathrm{Pb}\)