Ok so for question I have to state whether the element/compound is an acid, base, conjugate acid or conjugate base. Can u please tell me if i am correct and help me out with the ones i am unsure what the answer is?

Question

1)S^2-(aq)+HCl(aq)<=>Cl^1-(aq)+HS^1-(aq)
This is what I think the answer is:
Acid = HCl
Base = S^2-
Conjugate acid =Cl^1
Conjugate base = HS^1-

2)H2O2(aq)+PO4^3-(aq)<=>HPO4^2-(aq)+ HO2^1-(aq)
This is what I think it is:
Acid = H2O2
Base = PO4^3-
Conjugate acid =unsure
Conjugate base = unsure

3)IO3^1-(aq)+HI(aq)<=>I^1-(aq)+HIO3(aq)
This is what I think it is:
Acid = HI
Base = IO3
Conjugate acid =HIO3
Conjugate base = I^1-

4)H2SO4(aq)+CN^1-(aq)<=>HSO4^1-(aq)+ HCN(aq)
This is what I think it is:
Acid = H2SO4
Base = CN^1-
Conjugate acid =unsure
Conjugate base = unsure

Answer 1

Some right, some wrong. Here is the way you do it.

Example, your #4.
H2SO4 + CN^- <==>HSO4^- + HCN
You apparently have no trouble determining which is the acid and which is the base. All of them above are correct. Your problem is knowing what is the conjugate acid/base.
H2SO4 is the acid; therefore, what it goes to is the conjugate base which makes HSO4^- the conj base.
CN^- is the base; what it changes to is the conjugate acid. That is HCN