Question

Given below are two statements:
Statement I : In froth floatation method a rotating paddle agitates the mixture to drive air out of it.
Statement II : Iron pyrites are generally avoided for extraction of iron due to environmental reasons.
In the light of the above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are false
• B. Both Statement I and Statement II are true
• C. Statement I is false but Statement II is true
• D. Statement I is true but Statement II is false

Answer 1

The Correct Option is C

Statement I is false. In froth flotation, the primary purpose of the rotating paddle is to introduce air into the mixture, not to drive it out. The paddle helps create bubbles that attach to the mineral particles, making them float to the surface, where they can be collected as froth. This process is essential for the separation of valuable minerals from the gangue in the ore. Therefore, the statement that the paddle drives air out is incorrect.
Statement II is true. Iron pyrites (Fe\(S_2\)), when exposed to air and water, undergo oxidation and produce sulfuric acid. This acidic runoff is known as acid mine drainage (AMD), which can lead to severe environmental harm by contaminating water sources and soils. The acid dissolves heavy metals like copper and lead from surrounding rocks, further contributing to pollution. Hence, the statement about iron pyrites leading to acidic runoff is accurate.