Question

write a balanced net ionic equation for the reactions, if any, that occur between (a) ZnS(s) and HCl(aq); (b) K2CO3(aq) and Ca(NO3)2(aq); (c) Fe(NO3)2(aq) and H2S(aq); (d) Bi(OH)3(s) and HNO3(aq). Please show me molecular to complete ionic to net ionic as I need to understand how to do this, not just the answers.

Answer 1

i f you want under stand this you should know the what is the charge in each atom when it get dissociated in water

the we have to add the opposite counter ions then you have to balence

suppose lets take ZnS it will dissociate in to Zn²⁺ + S^2-

now HCl will dissociate in to H⁺ + Cl^- we have to add the opposite counter ions like Zn²⁺ and Cl^- but Zn need two electrons whereas with Cl having only one electron so you need two Cl^- to form ZnCl2 that we have to take two equilents of Hcl for one equilent of ZnS

net ionic equation we have to write two spices thai will insoluble product in water

lets consider the second reaction

here two possibilities are there

Ca will react with CO₃^2- can form CaCO3

another possibility is K+ can react with NO3- can form KNO3 but this will soluble in water so you dont need to write this one in net ionic equation

if there is no any precipitate that time we can write either because there is no use of net ionic equation.

a)

balenced equation

ZnS(s) + 2HCl (aq) -------> ZnCl₂(aq) + H₂S gas

net ionic equation is

S^2-   +2H⁺ --------> 2H₂S

b)

balenced equation is

K₂CO₃(aq) + Ca(NO₃)₂(aq) --> CaCO₃(s) + 2KNO₃(aq)

net ionic equation is

Ca²⁺(aq) + CO₃^2-(aq) --> CaCO₃(s)

c)

balenced equation is

Fe(NO₃)₂(aq) + H₂S(aq) --> 2HNO₃(aq) + FeS(s)

net ionic equation is

Fe²⁺(aq) + S^2-(aq) --> FeS(s)

d)

Bi(OH)₃ (s) + 3HNO₃ (aq) ----------> Bi(NO3)₃ (aq) + 3H₂O (aq)

net ionic equation is

3H⁺ + 3OH^- -------->     3H₂O (aq)