Write a net ionic equation for the reaction that occurs when aqueous solutions of sodium hydroxide and perchloric acid are combined.

It's done the same way the H2S and KOH were done.

well it said it was wrong the way it was done on the other one

Did you cancel the 2K^+ on each side? Did you check to see that the net equation was balanced; I omitted a coefficient of 2 for OH^-(aq). Do you know if the phase is supposed to be included?

To write the net ionic equation for the reaction between sodium hydroxide (NaOH) and perchloric acid (HClO4), we need to first write the balanced chemical equation.

The balanced equation for the reaction between NaOH and HClO4 is:

2 NaOH + HClO4 → Na2ClO4 + 2 H2O

Now, let's break down the equation into its ionic components. When NaOH dissolves in water, it dissociates into Na+ and OH- ions:

NaOH → Na+ + OH-

Similarly, when HClO4 dissolves in water, it dissociates into H+ and ClO4- ions:

HClO4 → H+ + ClO4-

Now, let's write the complete ionic equation by combining the appropriate ions:

2 Na+ + 2 OH- + H+ + ClO4- → Na2ClO4 + 2 H2O

In a net ionic equation, we exclude the spectator ions - the ions that remain the same on both sides of the equation. In this reaction, the Na+ and ClO4- ions on both sides are spectator ions. Therefore, the net ionic equation for the reaction is:

2 OH- + H+ → 2 H2O