KVPY2010Chemistryp Block Elements (Group 13 & 14)
Diborane is formed the elements as shown in equation (1) 2 ~B ( ~s )+3 H ₂( ~g ) B ₂ H ₆( ~g ) ..(1) Given that array ll H ₂ O (l) H ₂ O ( g ) & H ₁ ^ =44 ~kJ 2 ~B ( ~s )+3 / 2 O ₂( ~g ) B ₂ O ₃( ~s ) & H ₂ ^ =-1273 ~kJ ~B ₂ H ₆( ~g )+3 O ₂( ~g ) B ₂ O ₃( ~s )+3 H ₂ O ( g ) & H ₃ ^ =-2035 ~kJ H ₂( ~g )+1 / 2 O ₂( ~g ) H ₂ O (l) & H ₄ ^ =-286 ~kJ the H ^ for the reaction (1) is- & array
Options
- A36 ~kJ
- B509 ~kJ
- C520 ~kJ
- D-3550 ~kJ
Correct answer
A. 36 ~kJ
Step-by-step solution
(1) H ₂ O H ₂ O H =44 ~kJ ( ) (g) (2) 2 ~B + 1 3 O ₂ B ₂ O ₃ H =-1273 ~kJ (3) B ₂ H ₆+3 O ₂ B ₂ O ₃+3 H ₂ O (g) H =-2035 ~kJ (4) H ₂+1 / 2 O ₂ H ₂ O H =-286 ~kJ ( ) array l equation (2)+(4) 3+(1) 3-(3) H =(-1273)+(-286) 3+(44) 3-(-2035)=36 ~kJ array