Bond enthalpies of A2, B2 and AB are in the ratio 2: 1: 2. If bond enthalpy of formation of AB is -100 KJ mol -1 .The bond enthalpy of B 2 is

Question

Bond enthalpies of A2, B2 and AB are in the ratio 2: 1: 2. If bond enthalpy of formation of AB is -100 KJ mol -1 .The bond enthalpy of B 2 is (A) 100 KJ mol -1 (B) 50 KJ mol -1 (C) 200 KJ mol -1 (D) 150 KJ mol -1

Tardigrade Admin · Accepted Answer

Let bond enthalpy of A 2 be x , B 2 be ( x /2),AB be x A 2+ B 2 arrow 2 AB x +( x /2) 2x Δ H text form =(1/2) A 2+(1/2) B 2 arrow AB -100=(( x /2)+( x /4))- x x =400 B 2=( x /2)=200 kJ

Q. Bond enthalpies of $A_{2}$ , $B_{2}$ and $A B$ are in the ratio $2 : 1 : 2$ . If bond enthalpy of formation of $A B$ is $- 100 K J m o l^{- 1}$ .The bond enthalpy of $B_{2}$ is

$100 K J m o l^{- 1}$

$50 K J m o l^{- 1}$

$200 K J m o l^{- 1}$

$150 K J m o l^{- 1}$

Let bond enthalpy of $A_{2}$ be $x, B_{2}$ be $\frac{x}{2}, A B$ be $x$
$A_{2} + B_{2} \to 2 A B$
$x + \frac{x}{2} 2 x$
$Δ H_{form} = \frac{1}{2} A_{2} + \frac{1}{2} B_{2} \to A B$
$- 100 = (\frac{x}{2} + \frac{x}{4}) - x$
$x = 400$
$B_{2} = \frac{x}{2} = 200 k J$

Q. Bond enthalpies of A2​, B2​ and AB are in the ratio 2:1:2. If bond enthalpy of formation of AB is −100KJmol−1.The bond enthalpy of B2​ is

100KJmol−1

50KJmol−1

200KJmol−1

150KJmol−1