'Metals are usually not found as nitrates in their ores''. Out of the following two (`I`and `II`) reasons which is//are true for the above obervation?
`I`.Metal nitrates are highly unstable.
`II.` Metal nitrates are highly soluble in water.

Options

A. `I` and `II` are true
B. `I` and `II` are false
C. `I` is false but `II` is true
D. `I` is true but `II` is false

Answer

C

Explanation

Metals are usually not found as nitrates in their ores, because metal nitrates are highly soluble in water. For example, `KNO_3` (salt peter) would be classified as completely soluble. Thus, `KNO_3` could be expected to dissociate completely in aqueous solution to give `K^+` and `NO_3^-` ions.
`KNO_3 hArr K^(+)(aq) +NO_3^(-)(aq)`
The nitrate anion has three equivalent oxygen surrounding a central nitrogen atom. This tends to spread the single negative charge and make it easier for water (using hydrogen bonds) to separate the ions in solution.