Processes of Isolation of Elements — NEET UG practice

1. To find the correct set, check each statement against known industrial and chemical facts about these metals and alloys.

2. Statement (A): Chrome steel is a hard, corrosion-resistant alloy, making it well suited for cutting tools and crushing machinery, so this statement is correct.

3. Statement (B): Fine aluminium powder is commonly added to paints and lacquers to give them a bright, metallic finish, so this statement is correct.

4. Statement (C): Copper is mainly valued for its excellent electrical conductivity and is used in wiring and plumbing, not for reducing alcohols in chemical reactions, so this statement is incorrect.

5. Statement (D): Zinc dust can act as a reducing agent in various industrial processes, including in paint manufacturing, so this statement is correct.

6. Statement (E): In reality, it is zinc that is used to coat and protect iron (a process called galvanising), not the other way around, so this statement is incorrect.

7. Since statements (A), (B), and (D) are correct while (C) and (E) are incorrect,

Hence, the answer is C.

1. In the extraction of iron in a blast furnace, different reduction and reaction steps occur at different, specific temperature ranges as the materials move down through the furnace.

2. The reactions listed in options A, B, and C — the reduction of $\mathrm{FeO}$ to $\mathrm{Fe}$, the regeneration of $\mathrm{CO}$ from $\mathrm{CO}_2$ and carbon, and the formation of slag ($\mathrm{CaSiO}_3$) from $\mathrm{CaO}$ and $\mathrm{SiO}_2$ — are all known to occur within the 900 K to 1500 K range.

3. The reaction in option D, $\mathrm{Fe}_2\mathrm{O}_3 + \mathrm{CO} \rightarrow 2\mathrm{FeO} + \mathrm{CO}_2$, is actually the initial reduction step of iron ore, and this specific reaction occurs at a lower temperature range of 500 K to 800 K, not within the 900 K to 1500 K range asked about.

4. Since this reaction happens outside the specified temperature range,

Hence, the answer is D.

1. To match each mixture with its purification technique, consider the physical properties (boiling point, volatility, heat sensitivity) of the substances involved.

2. Glycerol from spent lye has a very high boiling point and decomposes if heated directly at normal atmospheric pressure, so it is purified using distillation under reduced pressure, which lowers the boiling point enough to avoid decomposition — matching (III).

3. Chloroform + Aniline is a mixture of two liquids with sufficiently different, manageable boiling points, so simple distillation is enough to separate them — matching (IV).

4. Fractions of crude oil contain many different hydrocarbons with a range of close boiling points, so fractional distillation is used to separate them into distinct fractions based on their boiling ranges — matching (II).

5. Aniline + Water involves an organic compound that is only slightly volatile in steam, so steam distillation is used, which allows aniline to distill over at a lower temperature along with steam — matching (I).

6. Putting it all together:

Hence, the answer is A.