Ammonium hexafluorosilicate contains NH4+ and [SiF6]^2-. How many atoms are present in one formula unit, and what is the oxidation number of Si?

JEE Advanced levelSingle correct optionDifficulty 3 of 3bn081

Ammonium hexafluorosilicate contains $NH X_{4} X^{+}$ and $[SiF X_{6}] X^{2 -}$ . How many atoms are present in one formula unit, and what is the oxidation number of Si?

Charge balance needs two

NH X_{4} X^{+}

(NH X_{4}) X_{2} [SiF X_{6}]

. Atoms:

2

+ 8

+ 1

+ 6

= 17

. Si:

x + 6 (- 1) = - 2

, so

x = + 4