Question

The idea of froth floatation method came from a person X and this method is related to the process Y of ores. X and Y, respectively, are:
A. Fisher woman and concentration
B. Washer man and reduction
C. Washer woman and concentration
D. Fisher man and reduction

Answer 1

Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic substances. This is used in mineral processing, paper recycling and waste-water treatment industries. Historically this was first used in the mining industry, where it was one of the great enabling technologies of the 20th century. It has been known as the single most important operation used for the recovery and upgrading of the sulfide ores.

Complete step by step answer:
The idea of froth floatation method came from washer woman and the method related to the froth floatation process is the concentration of the sulfide ores. Froth flotation is a process for selectively separating hydrophobic materials from the hydrophilic ones. In some cases, for example, sulfides ores of copper, zinc and lead concentration are brought by the froth floatation method. In this method, the advantage is taken of the preferential wetting of the ore by oil. The finely ground ore is taken in a tank containing water and 1% of pine oil or turpentine oil. A strong current of air is blown through the suspension, producing a heavy froth or foam on the surface. The metal sulfide is wetted by the oil but the gangues is not and the sulfide-oil mixture is carried to the surface by films of oil The froth is skimmed off, the gangue settles down on the bottom or remains underneath the froth. By this flotation method, it is possible to concentrate over 90% of a sulfide ore to one-tenth of its original bulk.

So, the correct answer is Option C.

Note:
During the flotation process of some ores, substances like gangue are added which activate or depress the flotation property of the minerals and thus, help in the separation of minerals present in the ore. For instance, galena $PbS$ is usually associated with sphalerite $ZnS$ and pyrites $NaCN$. .