According to the reaction equation:
and by using ICE table:
CN- + H2O ↔ HCN + OH-
initial 0.08 0 0
change -X +X +X
Equ (0.08-X) X X
so from the equilibrium equation, we can get Ka expression
when Ka = [HCN] [OH-]/[CN-]
when Ka = Kw/Kb
= (1 x 10^-14) / (4.9 x 10^-10)
= 2 x 10^-5
So, by substitution:
2 x 10^-5 = X^2 / (0.08 - X)
X= 0.0013
∴ [OH] = X = 0.0013
∴ POH = -㏒[OH]
= -㏒0.0013
= 2.886
∴ PH = 14 - POH
= 14 - 2.886 = 11.11
Answer: 460.624
Explanation:
1. Multiply the numbers
(24.5260 x 2.56) + 397.84
= (62.784) + 397.84
2. Add the numbers
(62.784) + 397.84
= 460.624
M=70.0 g
p=0.70 g/mL
v=m/p
v=70.0/0.70=100.00 mL
