Given the following equation: 3C12 (g) + 8NH3 (g) → N2(g) + ONH4Cl (S)
How many moles of NH3 are required to produce 12 moles of
NH4Cl?

The balanced equation will be your greatest asset in Solving this.

The Balanced Equation is

3Cl2 + 8NH3---> N2 + 6NH4Cl

So

From this reaction...

3 moles of NH3 is required to produce 6 moles of NH4Cl

Now the question asked How Many Moles of NH3 will be needed to produce 12moles of NH4Cl?...

The answer is simply 6moles of NH3.

Why?

Since 3moles of NH3 produce 6 moles of NH4Cl

It makes sense that

6moles of NH3 will produce 12moles of NH4Cl.

Its a simple Ratio.

Hope this helps...

I'm Open to questions if you have any.

Have a great Day!

well in order to answer this question you have to provide more information < 3