1. Farmers who raise cotton onve used arsenic acid, H3AsO4, as adefoliant at harvest time. Arsenic acid is a polyprotic acid withK1 = 2.5 * 10-14, K2 = 5.6 * 10-8 , and K3 = 3 * 10 -13 .
What is the pH of a 0.500 M sol'n of arsenic acid?
answer ) 1.96
3. A solution is prepared by adding 0.10 mol ofKCH3COO, to 1.00 L of water.
Which statement about the sol'n is correct?
a) the sol'n is basic.
b)the sol'n is neutral
c) the sol'n is acidic
d) the concentrations of K+ ions andCH3COO- ions will be identical
e) the concetnration of CH3COO- ions willbe greater than the concetnraion of K+ ions.
4. A sol'n is prepared by adding 0.10 mol of KCL, to 1.00 L ofwater. Which statement about the sol'n is correct?
a) the sol'n is basic
b) the sol'n is neutral
c) the sol'n is acidic
d)one need to know the temperature before any of the abovepredictions can be made.
e) the values for Ka and Kb for the species in sol'n must beknown before a prediction can be made.
I already knew the answers except #2, but I don't know thereason why.
Please explain the questions to me. Thanks!
