Silver precipitates in the presence of chlorides (white ppt). But it also precipitates in the presence of OH (brown ppt) and CO3 (brownish/white ppt).
Carbonates bubble in the presence of acids, but will it still bubble noticeably even though its only 0.1 M Na2CO3?
So, if I mix silver with the remaining solutions, I will get:
Na2CO3 (brownish/white ppt)
H2SO4 (no ppt)
HCl (white ppt)
NaOH (brown ppt)
That way, I could determine which one was H2SO4. The other three might be a little harder to tell. HCl would probably be the easiest to see since it is plain white. From there, I could mix the three solutions into the H2SO4, and whichever one bubbled would be Na2CO3. Then I would be left with HCl and NaOH. I would mix these together, checking for heat to confirm that they are in fact an acid/base. Then I could mix the Na2CO3 into them both, and whichever one bubbled would be HCl.
From there, I would want to do some confirmatory testing.
What are some other good tests I could use to determine Ba(NO3)2, Pb(NO3)2, HCl, H2SO4, NaOH and Na2CO3?