Answer:
The density (more precisely, the volumetric mass density; also known as specific mass), of a substance is its mass per unit volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D can also be used.
Answer:
HS+Na=>NaS+1/2H2(here HS- acts as an acid)
HS-. + HCl=> H2S(g)+ Cl-(here HS- acts as a base)