Question

Which of the reaction is suitable for concentrating ore by leaching process?

• A. $2 Cu _2 S +3 O _2 \rightarrow 2 Cu _2 O +2 SO _2$
• B. $Fe _3 O _4+ CO \rightarrow 3 FeO + CO _2$
• C. $Al _2 O _3+2 NaOH +3 H _2 O \rightarrow 2 Na \left[ Al ( OH )_4\right]$
• D. $Al _2 O _3+6 Mg \rightarrow 6 MgO +4 Al$

Answer 1

Answer: (C)

$Al _2 O _3+2 NaOH +3 H _2 O \rightarrow 2 Na \left[ Al ( OH )_4\right]$

Answer 2

The suitable reaction for concentrating ore by leaching process is:
$Al _2 O _3+2 NaOH +3 H _2 O \rightarrow 2 Na \left[ Al ( OH )_4\right]$
This is because the reaction involves the conversion of the metal oxide (in this case, aluminum oxide) into a water-soluble form (sodium aluminate), which can be easily separated from the impurities in the ore through leaching. Leaching involves dissolving the desired metal compound using a suitable solvent, in this case, sodium hydroxide solution. This process allows for the concentration of the ore by selectively dissolving the desired metal compound while leaving behind the impurities.

So, the correct option is (C).