Question

Q1.Q6.Two solutions A and B have pH 14 and 2 respectively. Which of the
solution will liberate hydrogen sulphide gas with zinc sulphide?

Answer 1

Explanation:

None of the solutions will be able to liberate Hydrogen sulphide gas when reacted with zinc sulphide.

But why?

1st case: (when pH = 2) , this means that the solution is an acid.

So, acids will liberate H+ ions, but hydrogen is below zinc in the reactivity series and hence will not be able to displace zinc from zinc sulphide.

$HCl + ZnS \neq H_{2}S + ZnHCl+ZnS</p><p></p><p>=H </p><p>2</p><p> </p><p> S+Zn$

2nd case: (when pH = 14), so the solution is basic/alkaline.

Base will release OH- ions which will convert ZnS to

$Na_{2}ZnO_{2} \: </p><p> </p><p> and \: Na_{2}S$

So, neither of the solutions will produce hydrogen sulphide gas.