Chemistry - Metallurgy Question with Solution | TestHub
How many statements are CORRECT?
(a) In spelter form, zinc can be separated by fractional crystallisation
(b) undergo heating at high temperature to give anhydrous
(c) In MacArthur forest cyanide process, the leaching reagent used is conc.
(d) In Hoop's process for electrolytic refining of aluminium molten metal will be collected from the bottom most layer
(e) In blast furnace,
reaction
takes place as the most prominent reaction at the portion where the temperature inside the furnace is highest.
(f) mThomas slag is calcium borate
Answer:
Solution:
(a) Incorrect. Spelter zinc contains impurities like Pb, Cd, Fe. It is refined by fractional distillation, not fractional crystallization, due to different boiling points.
(b) Incorrect. Heating at high temperatures leads to hydrolysis, forming and , not anhydrous .
(c) Incorrect. In the MacArthur-Forrest cyanide process, the leaching reagent for gold and silver is a dilute solution of sodium cyanide (), not concentrated .
(d) Incorrect. In Hoop's process, pure molten aluminum, being lighter, collects at the top layer, while the impure molten aluminum is at the middle layer, and the bottom layer consists of molten - alloy.
(e) Incorrect. The reaction occurs at lower temperatures (400-700 K) in the blast furnace, not at the highest temperature portion.
(f) Incorrect. Thomas slag is calcium phosphate, , formed during the Bessemer process for steel manufacturing, not calcium borate.
Therefore, none of the statements are correct.