Question

Consider the equlibrium equilibrium constant enery levels for specieT Reaction Coordinate What best characterizes the reaction? us at only K< 1 at low temperature, K > 1 " high temperature at only o, AS 0, KI at any temperature Hco, AS 0, K 1 at any temperature s at both(H . o. K > l at low at low temperature, K < I tt ΔΗ< 0, AS < 0, K high temperature (1) e both The data' show the variation in the b constant with temperat of Ba u What can be inferred from this plot? 18-wn 35. for 1 equi r 135 70 ial 7.5 I/T (K) n decreases with temperature. (A) Δ.G for the reactio (B) ΔΗ for the reaction is negative. (C) K increases with increasing temperature. (D) AS for the reaction is positive. with permission from James R. Horn, Donald Russell, Renrinted (adapted) Edwin A. Lewis Copyright (2001) American Chemical Society 174-178 001)

Answer 1

Q.34: Since energy of product B is less than that of the reactant A, energy is released. Hence this is an exothermic reaction and H < 0.

Since heat is released and n(g) is 0, S is also less than 0.

Since  H < 0 and S < 0, K>1 at low temperature and K <1 at high temperature.

Hence option (d) should be correct.

#35: ln(K) = ( - H / R)*(1/T) + S / R

For the given graph, slope =  - H / R > 0

=> H < 0

Hence H for the reaction is negative.

Also Y-intercept, C = S / R > 0

=> S > 0

Hence S is positive.

Since K is inversely proportional to T, K decreases with increase in temperature.

Since S is positive and H is negative, G is negative for any temperature.

Hence G for the reaction decreases with temperature. Hence

Hence (A), (B) and (D) are correct