No reaction SiO2 H3PO4

NaCl solid SiCl4 liquid PCl5 solid

HCl(g) H2O + NaCl(aq) AgCl(s) + NaNO3(aq)

In this part of the scheme two things are emphasized:

• Like the other hydrogen halides HCl is acidic in aqueous solution.
  Note however that HF is a weak acid: weak acid HF << HCl < HBr < HI strong acids
• One of the few cations that forms an insoluble chloride is Ag⁺. The other silver halides (except AgF) are also insoluble. Addition of AgNO₃(aq) to an acidified solution can be used to test for halide ion.