Chemistry problems?

on halogens:

8: The formula of a halogen acid used to etch glass is
a)HCl
b)HF
c)HBr
d)HI

9: The most stable of the following is
a)HF
b)HBr
c)HI
d)HCl

10: Bromine is freed from the bromine compounds in sea water by reaction with
a)chlorine
b)fluorine
c)iodine
d)radon

11: When chlorine water and carbon tetrachloride are mixed with an unkonwn, a violet layer is produced. The unknown is a(n)
a)fluoride
b)chloride
c)bromide
d)iodide

12: The order of activity of the halogens from greatest to least is:
a)F, Cl, I, Br
b)F, Cl, Br, I
c)Cl, F, Br, I
d)Cl, Br, I, F

13: In the laboratory preparation of bromine, manganese dioxide is used as
a)a catalytic agent
b)an inhibiting agent
c)an oxidizing agent
d)a reducing agent

14: A light sensitive substance used in photographic films has the formula
a)AgBr
b)CaF2
c)CuCl
d)MgBr2

and i’ll choose a best answer for who answers it first AND has the correct answer.