General principles and processes of isolation of elements practice · Medium

Option D (${Al}_2 \mathrm{O}_3$) is correct because aluminum has a higher affinity for oxygen than carbon, making it difficult to reduce with carbon.

Option A (Thorium) is correct because thorium is more abundant than uranium, radium, and radon in India.

Option D (Both i and iii) is correct because Van Arkel method and Mond's process both involve converting the metal to a volatile compound, separating it from impurities, and then decomposing it to obtain the pure metal.

Option C ($2\mathrm{F}{\mathrm{e}_2}{\mathrm{O}_3} + 3\mathrm{C} \to 4\mathrm{Fe} + 3\mathrm{C}{\mathrm{O}_2}$) is correct because the reduction of $Fe_2O_3$ primarily occurs via CO in the blast furnace, not directly with carbon.

Option D (To remove volatile substance) is correct because the main function of roasting is to remove volatile impurities from the ore.

Option D (Roasting) is correct because roasting involves heating sulfide ores in air to convert the sulfide to an oxide and release sulfur dioxide.

Option B (Al) is correct because aluminum is extracted by electrolytic reduction of alumina.

Option A (Pitch blende) is correct because radium is primarily obtained from pitchblende, a uranium-rich ore.

Option A (Roasting) is correct because roasting involves heating an ore in air below its melting point to remove volatile impurities or convert it into an oxide.

Option B (Different contents of carbon) is correct because the carbon content significantly affects the properties of cast iron, wrought iron, and steel.

Option B (Stibnite) is correct because stibnite ($\mathrm{S}{\mathrm{b}_2}{\mathrm{S}_3}$) is the primary ore from which antimony is extracted.

Option B (CO) is correct because carbon monoxide is the primary reducing agent for hematite in a blast furnace.

Option B (Antiknock compound) is correct because tetraethyl lead (TEL) was historically used as an antiknock agent in gasoline.

Option A (Hoop’s process) is correct because Hoop's process is specifically designed for the electrolytic refining of aluminum.

Option C (Na) is correct because Sodium is a highly reactive metal that is typically extracted through the electrometallurgical process (electrolysis of its molten salt).

The correct answer is C (If Assertion is True but the Reason is False) because sodium ethyl xanthate is used as a floating agent in froth floatation, but sulfide ores are generally insoluble in water.

Option A ($\mathrm{Fe}$) is correct because carbon reduction (smelting) is a common method for extracting iron from its oxide ores.

Option D ($\mathrm{As}$) is correct because Mispickel, also known as arsenopyrite, is a sulfide mineral of iron and arsenic with the formula $\mathrm{FeAsS}$.

Option D (Gangue and slag) is correct because in metallurgy, gangue is the impurity and slag is the product of flux and gangue.

Option B (Zinc) is correct because Zinc has a relatively low boiling point and can be purified by distillation.

Option D (If both Assertion and Reason and false) is correct because Carbonate and hydroxide ores are not concentrated by froth floatation, and mineral oil preferentially wets the ore particles, not gangue.

The correct answer is A ($\mathrm{SiO}_2$, iron oxides and $\mathrm{TiO}_2$) because bauxite, the principal ore of aluminum, typically contains silica, iron oxides, and titanium dioxide as major impurities.

The correct answer is C ($N{a_2}[Zn{(CN)_4}]$) because NaCN selectively reacts with ZnS to form this complex, preventing it from forming froth.

Option A (Both (A) and (R) are true and (R) is the correct explanation of (A)) is correct because cast iron is indeed different from pig iron, and the reason provided accurately describes how cast iron is made from pig iron with scrap iron and coke, resulting in a carbon content of about 3%.

Option B (${FeO}+{SiO}_2 \longrightarrow {FeSiO}_3$) is correct because this reaction does not primarily occur in the blast furnace during iron extraction.

Option D (All of these) is correct because smelting of iron involves combustion, reduction, and slag formation.

Option C (Electrolytic refining) is correct because aluminum is typically refined using electrolytic refining, specifically the Hall-Héroult process.

Option B (the three layers have different densities) is correct because the layers remain separate due to their differing densities, preventing mixing during electrolysis.

Option D (Pig iron) is correct because pig iron is an impure form of iron, not an ore.

Option B (Self reduction—carbon reduction) is correct because lead is extracted by self-reduction and tin is extracted by carbon reduction.