chemistry specimen paper question 10.1

first time user here!
I'm having a mega mind blank and cannot for the life of me gain a single mark on this question! Explanations would be amazing as I don't even know where to look for these answers in the AQA text book!
Thanks in advance!

The question:
Table 5 shows observations of changes from some test-tube reactions of aqueous solutions of compounds Q, R and S with five different aqueous reagents. The initial colours of the solutions are not given.


Table 5


BaCl2 + HCl
Q: no change
R: no change
S: white ppt

AgNO3+HNO3
Q: pale cream ppt
R: white ppt
S: no change

NaOH:
Q:white ppt
R: white ppt, dissolves in excess of NaOH
S: brown ppt

Na2CO3:
Q: white ppt
R: white ppt, bubbles of a gas
S: brown ppt, bubbles of a gas

HCL (conc)
Q: no change
R: no change
S: yellow solution

identify Q,R and S. You are not reqiured to explain your answers *although that would be mega helpful obviously xD*