Explanation:
Bayer process is industrial method of the refining of the bauxite to produce alumina which is aluminum oxide.
As alumina is amphoteric in nature, it exhibits a higher solubility at both the extremes of pH range, it is possible to dissolve alumina in low as well as in high pH solutions.
Dissolution of the alumina at high pH is well recognized in Bayer process. Bauxite is digested in very <u>high pH solution (> 13) of alkali</u> like sodium hydroxide at temperature of about 150–250°C and pressure at 20 atm. <u>This is done so that the dissolved alumina is separated from rest of insoluble bauxite minerals. </u>
Just choose 3
1) Lakes can form in hollows left by meteorite impacts (e.g. Clearwater Lakes, Quebec, Canada).
2) Lakes can form in the craters formed by volcanoes (e.g. Crater Lake, Oragon)
3) Lakes can form when a river is damed by a natural rock fall or man (e.g. Lake Mede)
4) Lakes can form where glaciers have scooped out the rock from the floor of a valley (e.g. Lake Geneva)
5) Lakes can form where block faulting lowers the land (e.g. lake Baikal)
6) lakes can form in natural depressions in the land (e.g. Lake Victoria)
I think it's Sodium Sulfide, because Na2S contains one Sodium and two Sulfur. Plus Sulfide<span> is used to describe any of three types of chemical compounds that contain sulfur.</span>
