Question

What is the net ionic equation for an acid-base reaction between solutions of $Ca(OH{)}_2$ and $H_{2}S$?

• A. $C{a}^{2+}+S^{2-}\to CaS$
• B. $H^{+}+O{H}^{-}\to H_{2}O$
• C. $H^{+}+C{a}^{2+}+S^{2-}+O{H}^{-}\to CaS+H_{2}O$
• D. $C{a}^{2+}+H_{2}S+2O{H}^{-}\to CaS+2H_{2}O$

Answer 1

Answer: (A)

$C{a}^{2+}+S^{2-}\to CaS$

The equation for acid-base reaction is:

$Ca(OH{)}_2+H_{2}S⟶CaS+2H_{2}O$

But in the ionic equation is as follows:

$Ca(OH{)}_2⟶C{a}^{2+}+2O{H}^{-}e{q}^n(1)$

$H_{2}S⟶2H^{+}+S^{2-}e{q}^n\left(2\right)$

From $1$ and $2$,

$C{a}^{2+}+S^{2-}+2H^{+}+2O{H}^{-}⟶CaS+2H_{2}O$

Now, $2H^{+}+2O{H}^{-}⟶2H_{2}O$

$\therefore$ The net ionic equation is

$C{a}^{2+}+S^{2-}⟶CaS$