Question

how many moles of o2 are needed to obtain 10 moles of h2o by reacting with h2.

Answer 1

H2+1/2(O2)-->H2O

1/2 mole of oxygen gives 1 mole of water

1/2xmoles of O2 gives 10 mole of water

=> 20 mole of oxygen gives 10 mole of water