Refining of crude Metal Questions in English

(A) Mond's Process is used for the purification of Nickel $(Ni)$. The reaction is: $Ni_{(s)} + 4 CO$ $\xrightarrow{330-350 \ K} Ni(CO)_{4(g)}$ $\xrightarrow{450-470 \ K} Ni_{(s)} + 4 CO$.
Van Arkel method is used for the purification of metals like Zirconium $(Zr)$ or Titanium $(Ti)$. The reaction is: $Zr_{(s)} + 2 I_{2(g)}$ $\xrightarrow{870 \ K} ZrI_{4(g)}$ $\xrightarrow{2075 \ K} Zr_{(s)} + 2 I_{2(g)}$.
Thus,$X$ is $Ni$ and $Y$ is $Zr$.

(C) Nickel is refined by the Mond process $(A-4)$.
Titanium is refined by the van-Arkel method $(B-3)$.
Germanium is refined by Zone refining $(C-2)$.
Copper is refined by Electrolytic refining $(D-1)$.
Therefore,the correct matching is $A-4, B-3, C-2, D-1$.

(D) The liquation method is used for refining metals that have low melting points,such as $Pb$,$Sn$,$Bi$,and $Hg$,compared to their impurities.
High melting point metals are not refined by this method.
Therefore,the statement that high melting metals are refined by liquation is incorrect.
Thus,option $(D)$ is the correct answer.

(C) Vapour phase refining involves the conversion of a metal into a volatile compound,which is subsequently decomposed to obtain the pure metal.
$1$. Nickel is purified by the Mond process: Impure nickel is heated in a stream of carbon monoxide to form a volatile complex,$Ni(CO)_4$,which is then decomposed to obtain pure nickel.
$Ni + 4 CO$ $\xrightarrow{350 \ K} Ni(CO)_4$ $\xrightarrow{470 \ K} Ni \text{ (pure)} + 4 CO$
$2$. Zirconium is purified by the Van Arkel method: Zirconium is heated in iodine vapours to form a volatile complex,$ZrI_4$,at $870 \ K$,which is further decomposed to obtain pure metal.
$Zr + 2 I_2$ $\xrightarrow{870 \ K} ZrI_4$ $\xrightarrow{1800 \ K} Zr \text{ (pure)} + 2 I_2$
Thus,the pair of metals refined by this method is $Zr$ and $Ni$.

(C) Zone refining is based on the principle that the impurities are more soluble in the melt than in the solid state of the metal.
This method is used for producing semiconductor grade metals of high purity,such as $Si$,$Ge$,$Ga$,and $In$.

(B) $a)$ Copper is refined by electrolytic refining,not the Van-Arkel method. Thus,this statement is incorrect.
$b)$ Zinc is refined by distillation,not electrolysis. Thus,this statement is incorrect.
$c)$ Zirconium is refined by the Van-Arkel method,not distillation. Thus,this statement is incorrect.
Therefore,all three statements $a, b,$ and $c$ are incorrect.

(C) $1$. Van Arkel method is used for the purification of metals like $Zr$ (Zirconium) and $Ti$ (Titanium). In this process,the crude metal is heated in an evacuated vessel with iodine to form a volatile metal iodide,which is then decomposed on a tungsten filament at high temperature to obtain pure metal.
$2$. Mond's process is specifically used for the purification of $Ni$ (Nickel). In this process,impure nickel is heated in a stream of carbon monoxide to form volatile nickel tetracarbonyl,$Ni(CO)_4$,which is then decomposed at higher temperatures to yield pure nickel.
$3$. Therefore,$A$ can be $Zr$ or $Ti$,and $B$ is $Ni$. Comparing with the options,$Zr$ and $Ni$ is a valid pair for $A$ and $B$ respectively.

(D) The principle of $Zone \ refining$ is that impurities are more soluble in the melt than in the solid state.
The $Vapour \ phase \ refining$ method is based on converting an impure metal into a volatile compound,which is then decomposed to obtain the pure metal.
The $Liquation$ method is based on the difference in melting points of the metal and the impurities,where the metal flows on a sloping surface.
The $Chromatographic$ method is based on the principle that different components of a mixture are adsorbed to different extents on an adsorbent. As the mobile phase moves through the stationary phase,these components separate based on their differential adsorption. Therefore,the correct option is $D$.

(B) Iodine is heated with zirconium to form a volatile compound which on further heating decomposes to give pure zirconium. This process is known as the Van Arkel method for refining metals.
Formation: $Zr + 2 I_2 \longrightarrow ZrI_4$ $(300-500^{\circ} C)$
Decomposition: $ZrI_4 \longrightarrow Zr + 2 I_2$ $(1100^{\circ} C)$

(A) The sphalerite ore is $ZnS$ (Zinc blende).
After extraction,the metal obtained is Zinc $(Zn)$.
Zinc has a low boiling point $(1180 \ K)$ and is volatile.
Therefore,it is purified by the process of distillation.

(B) Distillation is the process used to refine metals that have low boiling points,such as $Zn$,$Cd$,and $Hg$. In this method,the impure metal is heated to vaporize the pure metal,leaving behind the high boiling point impurities as a residue. The vapors are then condensed to obtain the pure metal.

(C) The correct matches are as follows:
$(A)$ Zone refining is used for the purification of semiconductors like $Ga, Si, Ge$. Thus,$A \rightarrow III$.
$(B)$ Poling is used for the purification of copper $(Cu)$ containing $Cu_2O$ as an impurity. Thus,$B \rightarrow IV$.
$(C)$ Liquation is used for metals with low melting points like tin $(Sn)$. Thus,$C \rightarrow II$.
$(D)$ Vapour phase refining is used for metals like $Ti$ and $Zr$ (Van Arkel method) or $Ni$ (Mond process). Thus,$D \rightarrow I$.
Therefore,the correct matching is $A-III, B-IV, C-II, D-I$.

(A) The Mond process is specifically used for the refining of nickel $(Ni)$.
The van Arkel method is used for the refining of metals like zirconium $(Zr)$ or titanium $(Ti)$.
Zone refining is used for producing semiconductors and other metals of very high purity,such as germanium $(Ge)$,silicon $(Si)$,boron $(B)$,gallium $(Ga)$,and indium $(In)$.
Therefore,$(X) = Ni$,$(Y) = Zr$,and $(Z) = Ga$.

(B) The principle of $Zone \ refining$ is that the impurities are more soluble in the melt state than in the solid state of the metal.
As the heater moves,the pure metal crystallizes out of the melt,while the impurities pass into the adjacent molten zone.
This method is particularly useful for producing semiconductors like $Ge$,$Si$,$Ga$,and for the purification of elements like $Boron$ $(B)$.
Therefore,the correct option is $B$.

(B) . Incorrect: In electrolytic refining of copper,pure $Cu$ is used as the cathode,and impure $Cu$ is used as the anode.
$B$. Correct: Zone refining is based on the principle that impurities are more soluble in the melt than in the solid state of the metal.
$C$. Correct: $TiI_4$ on heating decomposes to give pure $Ti$ (Van Arkel method). $TiI_4 \xrightarrow{>1100^{\circ} C} Ti + 2I_2$.
$D$. Incorrect: Very pure $Zr$ is obtained by the Van Arkel method,not galvanisation.
$E$. Incorrect: In copper smelting,hot air is used to convert $Cu_2S$ to $Cu_2O$ and then to metallic $Cu$ (self-reduction),not $CuSO_4$.
Thus,the correct statements are $B$ and $C$.

(A) Mond's process is a method used for the refining of nickel $(Ni)$.
In this process,impure nickel is heated in a stream of carbon monoxide $(CO)$ at a temperature of $330-350 \ K$ to form a volatile nickel tetracarbonyl complex: $Ni + 4CO \xrightarrow{330-350 \ K} Ni(CO)_4$.
This complex is then decomposed at a higher temperature $(450-470 \ K)$ to obtain pure nickel.

(B) Vapour phase refining is a technique used to purify metals by converting them into a volatile compound and then decomposing it to obtain the pure metal.
$1$. The Van Arkel method is used for refining $Zr$ and $Ti$.
$2$. The Mond process is used for refining $Ni$.
Therefore,$Zr$ is purified by vapour phase refining.