Bond enthalpies of H2, X2 and HX are in the ratio 2: 1: 2. If enthalpy of formation of HX is -50 kJ mol-1, the bond enthalpy of H2 is

Question

Bond enthalpies of H2, X2 and HX are in the ratio 2: 1: 2. If enthalpy of formation of HX is -50 kJ mol-1, the bond enthalpy of H2 is (A) 100 kJ mol-1 (B) 300 kJ mol-1 (C) 200 kJ mol-1 (D) 400 kJ mol-1

Tardigrade Admin · Accepted Answer

(1/2) H 2+(1/2) X 2 arrow HX Let bond enthalpy of X-X bond be x, then ⇒ (1/2) × 2 x +(1/2) × x -2 x =-50 ⇒ x +0.5 x -2 x =-50 KJ / mol ⇒ -0.5 x =-50 ⇒ x =(-50/-0.5)=100 KJ / mol

Q. Bond enthalpies of $H_{2}, X_{2}$ and $H X$ are in the ratio $2 : 1 : 2$ . If enthalpy of formation of $H X$ is $- 50 k J m o l^{- 1}$ , the bond enthalpy of $H_{2}$ is

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

$300 k J m o l^{- 1}$

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

$400 k J m o l^{- 1}$

Q. Bond enthalpies of H2​,X2​ and HX are in the ratio 2:1:2. If enthalpy of formation of HX is −50kJmol−1, the bond enthalpy of H2​ is

100kJmol−1

300kJmol−1

200kJmol−1

400kJmol−1

21​H2​+21​X2​→HX Let bond enthalpy of X−X bond be x, then ⇒21​×2x+21​×x−2x=−50 ⇒x+0.5x−2x=−50KJ/mol ⇒−0.5x=−50 ⇒x=−0.5−50​=100KJ/mol

Q. Bond enthalpies of $H_{2}, X_{2}$ and $H X$ are in the ratio $2 : 1 : 2$ . If enthalpy of formation of $H X$ is $- 50 k J m o l^{- 1}$ , the bond enthalpy of $H_{2}$ is

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

$300 k J m o l^{- 1}$

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

$400 k J m o l^{- 1}$