In this question, first, we have to find the limiting reagent.
Limiting Reagent:
-> Available in less than the stoichiometric amount.
-> Gets completely consumed in the reaction
-> Decides the amount of product.
So, according to the given reaction:
3Cu+8HNO3→3Cu(NO3)2+2NO+4H2O
We are given in question, 10 moles each of HNO3 and Cu
We know that 3 moles of Cu require 8 moles of HNO3
So, 10 moles of Cu will require =10×83 moles of HNO3
=26.66 moles of HNO3
Similarly, 8 moles of HNO3 require 3 moles of Cu
So, 10 moles of HNO3 will require =10×38 moles of Cu
3.75 moles of Cu
Therefore, since 10 moles of Cu will require 26.66 moles of HNO3 and we only have 10 moles of HNO3. So, HNO3 is the limiting reagent anf the reaction will take place accordingly.
Now, since 8 moles of HNO3 form 4 moles of H2O
So, 10 moles of HNO3 will form =10×48 moles of H2O
=5 moles of H2O