Exams › JEE Main › Chemistry
The enthalpy changes for the following processes are listed below: Cl2 (g) = 2Cl(g), 242.3 kJ mol−1 I2 (g) = 2I(g), 151.0 kJ mol−1 ICl(g) = I(g) + Cl(g), 211.3 kJ mol−1 I2 (s) = I2 (g), 62.76 kJ mol−1 Given that the standard states for iodine and chlorine are I2 (s) and Cl2 (g), the standard enthalpy of formation for ICl(g) is
- −14.6 kJ mol−1
- −16.8 kJ mol−1
- +16.8 kJ mol−1
- +244.8 kJ mol−1
Correct answer: +16.8 kJ mol−1
Solution
The standard enthalpy of formation for ICl(g) is calculated by considering the enthalpy changes of the constituent elements in their standard states. The formation reaction can be derived from the provided enthalpy values, leading to a net positive value of +16.8 kJ mol−1, indicating that the formation of ICl from its elements is endothermic.
Related JEE Main Chemistry questions
- Using the following thermochemical equations, determine the enthalpy of vaporisation of water: \[ \mathrm{H_2(g) + \tfrac{1}{2}O_2(g) \to H_2O(l)},\quad \Delta H = -286\ \text{kJ} \] \[ \mathrm{H_2(g) + \tfrac{1}{2}O_2(g) \to H_2O(g)},\quad \Delta H = -245.5\ \text{kJ} \]
- Given that the standard enthalpy of formation of NH$_3$ is $-46.0\ \text{kJ mol}^{-1}$, and the enthalpy of formation of H$_2$ from gaseous atoms is $-436\ \text{kJ mol}^{-1}$ while that of N$_2$ from gaseous atoms is $-712\ \text{kJ mol}^{-1}$, what is the average N–H bond enthalpy in NH$_3$?
- Using the following bond dissociation data, determine the enthalpy change for the conversion $8S(s) + \tfrac32 S_8(g)$.
- Using the bond enthalpies given below, determine the enthalpy change for the hydrogenation reaction shown: H–H bond energy = 431.37 kJ mol$^{-1}$ C–C bond energy = 606.10 kJ mol$^{-1}$ C–H bond energy = 336.49 kJ mol$^{-1}$ C–H bond energy = 410.50 kJ mol$^{-1}$ $C=C + H–H \rightarrow H–C–C–H$ What is the enthalpy change for this reaction?
- For a given reversible reaction, both enthalpy change ($\Delta H$) and entropy change ($\Delta S$) are positive. If $T_1$ denotes the equilibrium temperature, under which condition will the reaction be spontaneous?
- For the spontaneous reaction $2C_2H_6(g) + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)$, what are the signs of $\Delta H$, $\Delta S$, and $\Delta G$ in that order?
⚔️ Practice JEE Main Chemistry free + battle 1v1 →