How many moles of potassium hydroxide are needed to completely react with 2.94 moles of aluminum sulfate

Answer: - Third choice is correct, 17.6 moles

Solution: - The given balanced equation is:

Al_2 (SO_4) _3+6KOH/rightarrow 2Al (OH) _3+3K_2SO_4

We are asked to calculate the moles of potassium hydroxide needed to completely react with 2.94 moles of aluminium sulfate.

From the balanced equation, there is 1:6 mol ratio between aluminium sulfate and potassium hydroxide.

It is a simple mole to mole conversion problem. We solve it using dimensional set up as:

2.94molAl_2 (SO_4) _3 (/frac{6molKOH}{1molAl_2 (SO_4) _3})

= 17.6 mol KOH

So, Third choice is correct, 17.6 moles of potassium hydroxide are required to react with 2.94 moles of aluminium sulfate.