(vi) A solvent extraction in which two liquids move in opposite directions in continuous contact with each other.
(a) immiscible (b) miscible (c) polar
(d) non-polar​

(A). Immmiscible

Liquid/Liquid extraction is a solvent extraction in which two immiscible liquids move in opposite directions are in continuous contact with each other.

Explanation:

A liquid/liquid extraction is a method used to separate mixtures based on relative solubilities in two immiscible liquids, i.e., liquids that do not dissolve in each other but rather form separate layers when placed in the same glassware.

The immiscibility of the liquids is as a result of the two liquids having different polarities. One liquid is polar while the other is non polar, usually water which is polar and an organic solvent which is non-polar. The most common pair of extraction solvents used is diethyl ether or simply ether and water. They separate into layers and the position most each solvent in either the bottom or top layer is determined by its density. Ether is always found on the top layer while water is found innthe bottom layer because ether is less than than water. The density of ether is 0.713 g/cm3 and the density of H2O is 1.0 g/cm3.

The compound to be extracted dissolves into either of the layers based on the principle that like dissolves like. Polar compounds will dissolve into the water layer while organic nor non-polar compounds will dissolve in the ether layer. The compound is the extracted from either of the layer it is dissolved in.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.