A metal surface of 100 cm2 area has to be coated with nickel layer of thickness 0.001mm. A current of 2A was passed through a solution of Ni (NO3)2 for 'x' seconds to coat the desired layer. The value of x is_____ (Nearest integer) (PNi (density of Nickel) is 10 gmL-1, Molar mass of Nickel is 60 gmol-1 F = 96500 C mol-1)
To determine the value of 'x', we follow these steps: 1. Calculate the volume of Nickel (Ni) needed for the coating. Given the area is 100 cm2 and the thickness is 0.001 mm (which is 0.001 cm), the volume V is: V = area × thickness = 100 cm2 × 0.001 cm = 0.1 cm3. 2. Using density (PNi = 10 g/cm3), compute the mass of Ni required: mass = density × volume = 10 g/cm3 × 0.1 cm3 = 1 g. 3. Convert mass to moles using the molar mass (60 g/mol): moles of Ni = mass/molar mass = 1 g/60 g/mol = 1/60 mol. 4. From the electrochemical equivalent concept, calculate the charge required using: charge (Q) = moles × Faraday constant (F = 96500 C/mol), thus Q = (1/60) × 96500 C ≈ 1608.33 C. 5. Find 'x' using the relationship between charge, current (I = 2 A), and time (x): Q = I × x ⇒ x = Q/I = 1608.33 C/2 A ≈ 804.17 s. 6. Round to the nearest integer and verify the solution is in the provided range 161,161: x ≈ 804 seconds, which is indeed within the expected range.
