Question

The following balanced equation shows the formation of water.

Answer 1

Mole ratio of H₂  :  O₂   is   2  :  1

∴ if mole of H₂  =  1.67 mol

then mole of O₂ =  $\frac{1.67 mol}{2}$

⇒ that mole of oxygen needed to react with H₂  =  0.835 mol

The answer is A

Answer 2

Answer: A) 0.835 mol of $O_2$

Explanation: According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

As can be seen from the given balanced equation:

$2H_2+O_2\rightarrow 2H_2O$

2 moles of hydrogen are required to react completely with 1 mole of oxygen.

Thus 1.67 moles of hydrogen will react with=$\frac{1}{2}\times 1.67=0.835$ moles of oxygen.