When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of A ?

Question

When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of A ? (A) C 11 H 8 (B) C 11 H 4 (C) C 5 H 8 (D) C 9 H 8

Tardigrade Admin · Accepted Answer

C x H y +( x +( y /4)) O 2 arrow xCO 2+( y /2) H 2 O ( y /2)=4 ∴ y =8 x +(8/4)=11 ∴ x =9 ∴ Hydrocarbon will be= C 9 H 8

Q. When a hydrocarbon A undergoes complete combustion it requires $11$ equivalents of oxygen and produces $4$ equivalents of water. What is the molecular formula of $A$ ?

$C_{11} H_{8}$

$C_{11} H_{4}$

$C_{5} H_{8}$

$C_{9} H_{8}$

$C_{x} H_{y} + (x + \frac{y}{4}) O_{2} \to x C O_{2} + \frac{y}{2} H_{2} O$
$\frac{y}{2} = 4 ∴ y = 8$
$x + \frac{8}{4} = 11$
$∴ x = 9$
$∴$ Hydrocarbon will be $= C_{9} H_{8}$

Q. When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of A ?

C11​H8​

C11​H4​

C5​H8​

C9​H8​