Assertion: When a salt such as NaCl dissolves, the Na+ and Cl- ions leaving the crystal lattice acquire far greater freedom.
Reason: In thermodynamic terms, the formation of solution occurs with a favourable change in free energy, i.e., ΔH has a high positive value and TΔS a low negative value.
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
(e) If the Assertion is incorrect but the Reason is correct.
(c) If the Assertion is correct but Reason is incorrect.
Explanation:
In NaCl crystal Na+ and Cl- are strongly bonded due to electrostatic attraction. As it is dissolved in solvent, Na+ and Cl- acquire greater freedom. In thermodynamic terms formation of solution occurs with a favourable change in ΔG. TΔS is largely –ve which overcomes the small +ve value of ΔH. Thus ΔG is negative for dissolution of salt. Hence assertion is true but reason is false.