the answer
the equation of reaction is
Cu + 4HNO3 →→ Cu(NO3)2 + 2NO2 + 2 H2O
1mole 4 moles 1mole 2 moles 2 moles
0.0424 mol ----> 0.160 mol ???? moles
we can find it by applying mole ration formula,
1/0.0424 =2/ n H2O or 4/0.16= 2/nH2O
nH2O is the number of mole that has been formed
so 1x nH2O =2 x 0.0424=> nH2O= 0.0848 moles
or 4x nH2O= 2x0.16=> nH2O= 0.08 moles
so the answer is 0.0848 moles