Answer: Option C; K3N
Explanations:
1. Calculate number of moles for K and N
(i) Moles for K
mass = 89.3% = 89.3g
Mol. mass K =39.0983g/mol
∴ n = mass/molmass
=89.3/39.0988
=2.28 moles
(ii) Moles for N
mass = 10.7% = 10.7 g
Mol. mass N =14.0067g/mol
∴ n = mass/molmass
=10.7g/ 14.0067g/mol
=0.76 moles
2. Divide all components by the smallest value:
• K= 2.28 /0.76 = 2.9898240669737 ≈ 3
• N=0.76/0.76 = 1
Therefore emperical formula has 3 K and 1 N = K3N