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A: Molten aluminium chloride when electr...

A: Molten aluminium chloride when electrolysed using 0.1F, deposits 0.1g equivalent of aluminium.
R: Mass of substance deposited `alpha` quantity of electricity.

A

If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)

B

If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)

C

If Assertion is true statement but Reason is false, then mark (3)

D

If both Assertion and Reason are false statements then mark (4)

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we need to analyze the assertion (A) and the reason (R) provided in the question. ### Step 1: Understanding the Assertion The assertion states that "Molten aluminium chloride when electrolyzed using 0.1F, deposits 0.1g equivalent of aluminium." ### Step 2: Understanding the Reason The reason states that "Mass of substance deposited is directly proportional to the quantity of electricity." This is a fundamental principle of electrochemistry, known as Faraday's laws of electrolysis. ### Step 3: Applying Faraday’s Laws According to Faraday's first law of electrolysis: \[ W = Z \times Q \] Where: - \( W \) = mass of the substance deposited (in grams) - \( Z \) = electrochemical equivalent (in grams per coulomb) - \( Q \) = quantity of electricity (in coulombs) ### Step 4: Finding the Electrochemical Equivalent (Z) The electrochemical equivalent \( Z \) can be calculated using the formula: \[ Z = \frac{M}{nF} \] Where: - \( M \) = molar mass of aluminum = 27 g/mol - \( n \) = number of electrons transferred (n-factor) = 3 for Al³⁺ to Al - \( F \) = Faraday's constant = 96500 C/mol Substituting the values: \[ Z = \frac{27}{3 \times 96500} = \frac{27}{289500} \approx 9.33 \times 10^{-5} \text{ g/C} \] ### Step 5: Calculating the Quantity of Electricity (Q) Given that the current is 0.1 Faraday, we convert this to coulombs: \[ Q = 0.1 \times 96500 = 9650 \text{ C} \] ### Step 6: Calculating the Mass Deposited (W) Now, we can calculate the mass of aluminum deposited: \[ W = Z \times Q = (9.33 \times 10^{-5}) \times 9650 \approx 0.9 \text{ g} \] ### Step 7: Finding the Gram Equivalent To find the gram equivalent of aluminum deposited: \[ \text{Gram Equivalent} = \frac{W}{n} = \frac{0.9}{3} = 0.3 \text{ g equivalent} \] ### Step 8: Conclusion The assertion states that 0.1 g equivalent of aluminum is deposited, but we calculated that 0.3 g equivalent is deposited. Therefore, the assertion is false. Since the reason is a true statement, but it does not support the assertion, the reason is also considered false in this context. ### Final Answer Both the assertion (A) and the reason (R) are false. ---
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