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Read following statement(s) carefully an...

Read following statement(s) carefully and select the right option :
(I) The enthalpy of solution of `CaCl_(2). 6H_(2)O` in a large volume of water is endothermic to the extent of 3.5 kcal/mol. If `DeltaH=-23.2 " kcal"` for the reaction,
`CaCl_(2)(s)+6H_(2)O(l)rarrCaCl_(2).6H_(2)O(s)`
then heat of solution of `CaCl_(2)` (anhydrous) in a large volume of water is - 19.7 kcal/mol
(II) For the reaction `2Cl(g)rarrCl_(2)(g)`, the sign of `DeltaH` and `DeltaS` are negative.

A

Statement I and II both are wrong

B

both are correct

C

only I is correct

D

only II is correct

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we will analyze both statements provided and determine their correctness step by step. ### Step 1: Analyze Statement I We are given the following information: 1. The enthalpy of solution of `CaCl2.6H2O` in a large volume of water is endothermic to the extent of 3.5 kcal/mol. This means: \[ \Delta H_{\text{solution}}(CaCl2.6H2O) = +3.5 \text{ kcal/mol} \] 2. The reaction for the formation of `CaCl2.6H2O` from `CaCl2` and water is given as: \[ CaCl2(s) + 6H2O(l) \rightarrow CaCl2.6H2O(s) \] with: \[ \Delta H = -23.2 \text{ kcal} \] 3. We need to find the heat of solution of anhydrous `CaCl2` in a large volume of water. ### Step 2: Write the Reaction for Anhydrous `CaCl2` The reaction for the dissolution of anhydrous `CaCl2` in water can be represented as: \[ CaCl2(s) + nH2O(l) \rightarrow CaCl2.nH2O(s) \] ### Step 3: Apply Hess's Law According to Hess's Law, the total enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps. We can combine the two reactions: 1. The dissolution of `CaCl2.6H2O`: \[ CaCl2.6H2O(s) \rightarrow CaCl2(s) + 6H2O(l) \quad \Delta H = +3.5 \text{ kcal} \] 2. The formation of `CaCl2.6H2O` from `CaCl2` and water: \[ CaCl2(s) + 6H2O(l) \rightarrow CaCl2.6H2O(s) \quad \Delta H = -23.2 \text{ kcal} \] When we add these two reactions, we get: \[ CaCl2.6H2O(s) + 6H2O(l) + CaCl2(s) \rightarrow CaCl2(s) + 6H2O(l) + CaCl2.6H2O(s) \] ### Step 4: Calculate the Total Enthalpy Change Now, we can calculate the overall enthalpy change: \[ \Delta H_{\text{total}} = +3.5 \text{ kcal} + (-23.2 \text{ kcal}) = -19.7 \text{ kcal} \] Thus, the heat of solution of anhydrous `CaCl2` in a large volume of water is: \[ \Delta H_{\text{solution}}(CaCl2) = -19.7 \text{ kcal/mol} \] ### Conclusion for Statement I This means Statement I is correct. ### Step 5: Analyze Statement II For the reaction: \[ 2Cl(g) \rightarrow Cl2(g) \] 1. **Enthalpy Change (ΔH)**: The formation of a bond (Cl-Cl) releases energy, indicating that ΔH is negative. 2. **Entropy Change (ΔS)**: The number of gaseous moles decreases from 2 moles of Cl to 1 mole of Cl2, indicating a decrease in disorder. Thus, ΔS is also negative. ### Conclusion for Statement II Both ΔH and ΔS are negative, making Statement II correct. ### Final Answer Both statements are correct. Therefore, the correct option is **B**. ---

To solve the question, we will analyze both statements provided and determine their correctness step by step. ### Step 1: Analyze Statement I We are given the following information: 1. The enthalpy of solution of `CaCl2.6H2O` in a large volume of water is endothermic to the extent of 3.5 kcal/mol. This means: \[ ...
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