Question

Under what geochemical conditions is uranium soluble in water as an ion with 6+ charge? [Select ALL answers that apply]

		Oxidizing and strongly acidic.
		Reducing and strongly acidic.
		Oxidizing and strongly basic.
		Reducing with neutral pH.
		Oxidizing with neutral pH.
		Reducing and strongly basic.

Answer 1

Uranium is naturally occurring and predominantly found in groundwater in the Western Central Platform, the Rocky Mountain System etc.

Granite, metamorphic rocks, lignites, monazite sand, and phosphate deposits typically contain uranium.

Before it is transported into water, however, it must be oxidized.

Uranium can exist in five oxidation states:

+2,+3,+4,+5 and +6. However, only the +4 and +6 states are stable enough to be of practical importance.

Tetravalent uranium is reasonably stable and forms hydroxides,hydrated fluorides and phosphates of low solubility.

Hexavalent uranium is the most stable state and the most commonly occurring form is U3O8.

Major compounds of uranium include oxides, fluorides, carbides, nitrates,

chlorides, acetates and others.

U3O8 is soluble in acids like HNO3 and H2SO4. It has basic nature.

UF6 is covalent in nature and soluble in CCl4 and chloroform.

The option will be Oxidizing and strongly basic.