Which of the following buffer solutions would be most effective?

a.) .01M HClO2/0.01 M KClO2
b.) 0.05 M HCN/0.05 M NaCN
c.) 1.00 M HBr/1.00 M LiBr
d.) 1.00 M HNO/1.00 M KNO2

Which of the following compounds will be more soluble in acidic solution than pure water?
a) PbBR2
FeS
c) Ca(ClO4)2
d)CuI

For a titration of weak acid with a strong base, the pH of the endpoint was 9.0. Which indicator (with their respective pH ranges) woould be the most useful in identifying the endpoint?

a) m-Nitrophenol ph range = 6.9-8.5)
b. Phenolphthalen (pH range 8.5-10.0)
c) Alizarin Yellow R pH range 10.0-12.0)
d) None of the above

pretty sure this is b.