What mass of silver is deposited during electrolysis when a current of 0.8 A flows for 25 minutes?
A
0.22 g
B
1.86 g
C
0.14 g
D
1.34g
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Answer: D
To calculate the mass of silver deposited during electrolysis, we use the formula:
\(m = \frac{Q \cdot M}{n \cdot F}\)
Where: \( I = 0.8 \, \text{A} \), \( t = 25 \, \text{minutes} = 25 \times 60 = 1500 \, \text{s} \), \( Q = I \cdot t = 0.8 \, \text{A} \cdot 1500 \, \text{s} = 1200 \, \text{C} \)
\( M = 107.87 \, \text{g/mol} \), \( n = 1 \), \( F \approx 96485 \, \text{C/mol} \)
Substituting the values:
\(m = \frac{1200 \, \text{C} \cdot 107.87 \, \text{g/mol}}{1 \cdot 96485 \, \text{C/mol}} = \frac{129444}{96500} \approx 1.34 \, \text{g}\)
Source: Myschool Past Questions Archive (Record #74387)