22 ionization for 12 Msolution of hydeofuoric acid given tha

22. ionization for 1.2 Msolution of hydeofuoric acid given that the Ka for (18 points) is 1AN ph pOn HF P1 TH\'1 Percent order kinetics with a rate 23. The decomposition of an insecticide in water follows 1* constant of 1.62 yr at 20°C. If a sample of water at 20°C contains this insecticide and has a concentration of 5.23 x 10+ moles/L, a) what will the concentration be one year from now? b) how long will it take for the concentration of the insecticide to decrease to 2.11 x 104 moles/L (12 points)?

Solution

(23)

Using the first order decay equation:

A = A₀*e^-kt

Data given:

A₀ = 0.000523

k = 1.62 yr^-1

Putting values:

A = 0.000523*e^-1.62*1

Solving we get:

A = 1.035*10^-4 M

(b)

Putting values:

0.000211 = 0.000523*e^-1.62*t

Solving we get:

t = 0.56 years

Hope this helps !