Mass of sulfur combined - 4.69 g
Mass of gas produced is 15.81 g, therefore mass of fluorine is (15.81-4.69) = 11.12 g
Number of sulfur moles - 4.69 g/32 g/mol = 0.15 mol
Number of fluorine moles - 11.12 g/ 19 g/mol = 0.585 mol
divide both by least number of moles
S - 0.15/0.15 = 1
F - 0.585/0.15 = 3.9 rounded off is 4
ratio of S to F = 1:4Therefore formula of the gas is SF₄
"NH4+ <----> NH3 + H+
The constant of this equilibrium is: K = Kw / Kb = 1 x 10^-14 / 1.8 x 10^-5 =5.56 x 10^-10
5.56 x 10^-10 = x^2 / 0.20-x
x = [H+] =1.1 x 10^-5 M
pH = 5.0"
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