9701/11/O/N/12

[obaid-ur-rehman]

can any one help me in
chemistry 9702 p11 (variant 1) oct nov 2012 question 11 (9701/11/O/N/12 q11)
http://freeexampapers.com/A-Level/Chemistry/CIE/2012-Nov/9701_w12_qp_11.pdf

 

[Mathemagical]

can any one help me in
chemistry 9702 p11 (variant 1) oct nov 2012 question 11 (9701/11/O/N/12 q11)
http://freeexampapers.com/A-Level/Chemistry/CIE/2012-Nov/9701_w12_qp_11.pdf

The answer is A.

Let n be 3. The compound would be XY3, so the reaction would look like this:

XY3 --> X + 3Y

From this, we can see that 3 X-Y bonds are broken, so the bond enthalpy of X-Y would be the reaction enthalpy divided by 3.
Substituting any value of n would yield the same result, so the answer is A.