The Ka value for HCN is 4.9x10^-10. What is the value of Kb for CN-?
KaKb = K = 1E-14
To find the value of Kb for CN-, we can use the relationship between Ka and Kb for a conjugate acid-base pair.
The conjugate base of an acid is formed when the acid donates a proton (H+). In this case, HCN is the conjugate acid and CN- is its conjugate base.
The relationship between Ka and Kb is given by the equation:
Ka * Kb = Kw
Where Kw is the water ionization constant, equal to 1.0 x 10^-14 at 25°C.
Rearranging the equation, we have:
Kb = Kw / Ka
Now, substitute the known values:
Kw = 1.0 x 10^-14
Ka = 4.9 x 10^-10
Kb = (1.0 x 10^-14) / (4.9 x 10^-10)
Performing the calculation, we get:
Kb = 2.04 x 10^-5
Therefore, the value of Kb for CN- is approximately 2.04 x 10^-5.