By means of what single reagent could you distinguish between the following? (Tell what happens to each substance.)

Question

Solutions:
AgNO3 and Zn(NO3)2
H2SO4 and HNO3
Ag(NH3)2Cl and AgNO3
Solids:
AgCl and ZnCl2
AgCl and Hg2Cl2
PbCrO4 and K2CrO4

Answer 1

You're supposed to use your knowledge of chemistry to answer these.
The first one, AgNO3 and Zn(NO3)2.
Add NaCl. The AgNO3 reacts with NaCl to produce a white insoluble precipitate of AgCl. Zn(NO3)2 and NaCl does nothing. So the secret is to know the solubility tables. Where a ppt will not form, the usual test is something that produces a colored complex ion, or something similar.

For the solids.
Add H2O. AgCl is insoluble. ZnCl2 dissolves easily.

Now you try the others.