GATE 2020 MT – Question 16

Physical Metallurgy · Corrosion · 1 mark · Multiple choice

Which statement about selective leaching of a binary alloy is TRUE?

The lower atomic-weight element is leached.
The higher-diffusivity element is leached.
The more electronegative element is leached.
The lower-density element is leached.

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Correct answer: (C) The more electronegative element is leached.

Explanation

The appended key selects C, and that grading is preserved. Selective leaching removes the electrochemically more active, less noble constituent, leaving a porous residue enriched in the nobler component. Atomic weight and density do not determine that electrochemical preference, and diffusivity alone is not the criterion. The printed word “electronegative” is problematic if read as ordinary chemical electronegativity: the intended meaning is the constituent with the more negative electrode potential, not necessarily the more electronegative element on an atomic electronegativity scale.

GATE 2020 MT – Question 16

Explanation

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