jika diketahui pH NH4Br = 6 ,kb NH4Br = 10—5,dan mr NH4Br = 98,masa amonium bromida yang harus dilarutkan dalam 500 mL air sebanyak..mg

pH = -log H+
H+ = 10^-6

H+ = √ kw / kb x Mg
10^-6 = √ 10^-14 / 10^-5 x Mg
10^-12 = 10^-9 x Mg
Mg = 10^-3

M = n / V
10^-3 = n / 0.5
n = 5 x 10^-4

massa = n x Mr
massa = 5 x 10^-4 x 98
massa = 498 x 10^-4
massa = 4.98 x 10^-2 g = 49.8 mg