Q. 0.75 moles of a solid $A_{4}$ and 2 moles of $O_{2}(g)$ are heated in a sealed vessel, completely using up the reactants and produces only one compound. It is found that when the temperature is used to initial temperature, the contents of the vessel exhibit a pressure equal to $\frac{1}{2}$ of the original pressure. The formula of the product will be
A) $A_{2}O_{3}$
B) $A_{3}O_{8}$
C) $A_{3}O_{4}$
D) $AO_{2}$
Explanation
(c)
As both the reactants are consumed completely, thus the ratio of stoichiometric coefficients would be 0.75 : 2 or 3:8
So,
$3A_{4} + 8O_{2} \longrightarrow Product$
Now as final pressure is half of oxygen initially, thus the molecular formula will be $A_{3}O_{4}$ to balance the equation correctly, $ie$,
$3A_{4} + 8O_{2} \longrightarrow 4A_{3}O_{4}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.