Answer : The correct option is, (1) 2.5 moles
Solution : given,
Moles of [tex]C_2H_2[/tex] = 1 mole
The given balanced reaction is,
[tex]2C_2H_2(g)+5O_2(g)\rightarrow 4CO_2(g)+2H_2O(g)[/tex]
From the balanced reaction, we conclude that
As, 2 moles of [tex]C_2H_2[/tex] react with 5 moles of [tex]O_2[/tex]
So, 1 mole of [tex]C_2H_2[/tex] react with [tex]\frac{5}{2}=2.5[/tex] moles of [tex]O_2[/tex]
Therefore, the number of moles of oxygen required is, 2.5 moles.
