$\ce{CsCl}$ and $\ce{NH4Cl}$ have similar reactions. For example, they can react with $\ce{AgNO3}$ to produce $\ce{AgCl}$ precipitate.
So my question is:
Can we use a chemical test to distinguish between solid $\ce{CsCl}$ and $\ce{NH4Cl}$?
The $\ce{Cs+}$ ion is very unreactive and I do not know any reactions involving it. I believe the chemical test can somehow convert the $\ce{NH4+}$ ion into $\ce{NH3}$ gas so that we can test it with a moist red litmus paper.