Question

0.75 mole of solid ‘$A_4$’ and 2 moles of gaseous $O_2$ are heated in a sealed vessel, completely using up the reactants and producing only one compound. It is found that when the temperature is reduced to the initial temperature, the contents of the vessel exhibit a pressure equal to half the original pressure. What conclusions can be drawn from these data the product of the reaction?

• A. $A_2{O}_5$
• B. $A_3{O}_4$
• C. $A_2{O}_2$
• D. none of these

Answer 1

The correct option is B $A_3{O}_4$

give reaction

$A_4\left(s\right)+O_2\left(g\right)\to A_x{O}_y$

Applying POAC law for A atoms,

4 × moles of $A_4=x\times molesof{A}_x{O}_y$

=> $4\times 0.75=x\times 1$

=> x = 3

Applying POAC for O atoms,

$2\times molesof{O}_2=y\times molesof{A}_x{O}_y$

=> $2\times 2=y\times 1$

=> y = 4

Thus, the formula of the product is $A_3{O}_4$.