Question

Which metal is obtained by self reduction process ? or Where the proportionally constant k is called rate constant

Answer 1

metals like Cu and Hg can be auto reduced
k becomes rate constant when the order of reaction is zero

Answer 2

copper, lead and mercury are all less electropositive metals and so they can be extracted by self-reduction from their respective sulphide ores. In the extraction of copper from its sulphide ore, the ore is subject to partial roasting in air to from its oxide.