Electrolysis of Ni(NO3)2

Introduction:
Electrolysis is a process that uses an electric current to drive a non-spontaneous chemical reaction. It involves the breaking down of a compound into its constituent elements by passing an electric current through it. In this case, we will be electrolyzing a solution of Ni(NO3)2 using platinum electrodes to produce nickel at the cathode.

Given Information:
- Current (I) = 0.5 ampere
- Time (t) = 20 minutes = 20 x 60 seconds = 1200 seconds
- Ni(NO3)2 is the electrolyte

Step 1: Calculating the number of moles of electrons
To determine the amount of nickel produced, we need to find the number of moles of electrons transferred during the electrolysis. This can be calculated using Faraday's laws of electrolysis, which states that the amount of substance produced or consumed in an electrolysis reaction is directly proportional to the quantity of electricity passed through the cell.

The formula to calculate the number of moles of electrons (n) is:
n = (I x t) / (F x z)
Where:
- I is the current in amperes
- t is the time in seconds
- F is Faraday's constant (96485 C/mol)
- z is the number of electrons involved in the reaction

In this case, since Ni(NO3)2 is being electrolyzed, the balanced equation for the reaction at the cathode is:
Ni2+ + 2e- → Ni

From the balanced equation, we can see that 2 moles of electrons are involved in the reduction of 1 mole of Ni2+.

Therefore, z = 2 in this case.

Substituting the given values into the formula, we get:
n = (0.5 A x 1200 s) / (96485 C/mol x 2)

Step 2: Calculating the moles of Ni produced
Next, we need to calculate the moles of nickel produced at the cathode. Since each mole of nickel is produced by the transfer of 2 moles of electrons, the moles of nickel (nNi) can be calculated as:
nNi = n / 2

Step 3: Calculating the mass of Ni produced
Finally, we can calculate the mass of nickel produced by multiplying the moles of nickel by its molar mass (58.69 g/mol):
Mass of Ni = nNi x Molar mass of Ni

Conclusion:
By following the above calculations, we can determine the weight of nickel produced at the cathode during the electrolysis of Ni(NO3)2 using a current of 0.5 ampere for 20 minutes. The weight of nickel can be obtained by converting the moles of nickel produced to grams using its molar mass.