Question 188 of 949
A current of 0.5 A flowing 3h Deposits 2g of metal during electrolysis. The quantity of the same metal that would be deposited by the currents of 1.5A flowing in 1h is
- A. 2g
- B. 6g
- C. 10g
- D. 18g
Correct Answer:
A
Explanation
To solve the problem of how much metal will be deposited during electrolysis with a different current and time, we can use Faraday's laws of electrolysis. Let's break down the problem step-by-step.
### Step 1: Understand the relationship between current, time, and mass deposited
Faraday's first law of electrolysis states that the mass (m) of a substance deposited during electrolysis is directly proportional to the quantity of electricity (Q) passed through the electrolyte. The relationship can be expressed mathematically as:
\[ m = k \cdot Q \]
where:
- \( m \) is the mass of the substance deposited (in grams),
- \( k \) is a constant that depends on the substance and its valency,
- \( Q \) is the total electric charge passed (in coulombs).
The total electric charge \( Q \) can be calculated using the formula:
\[ Q = I \cdot t \]
where:
- \( I \) is the current (in amperes),
- \( t \) is the time (in seconds).
### Step 2: Calculate the charge for the first scenario
In the first scenario, we have:
- Current \( I_1 = 0.5 \, \text{A} \)
- Time \( t_1 = 3 \, \text{h} = 3 \times 3600 \, \text{s} = 10800 \, \text{s} \)
Now, we can calculate the total charge \( Q_1 \):
\[ Q_1 = I_1 \cdot t_1 = 0.5 \, \text{A} \cdot 10800 \, \text{s} = 5400 \, \text{C} \]
### Step 3: Determine the mass deposited in the first scenario
According to the problem, this charge deposits 2g of metal. Therefore, we can express this relationship as:
\[ 2 \, \text{g} = k \cdot 5400 \, \text{C} \]
From this, we can find the constant \( k \):
\[ k = \frac{2 \, \text{g}}{5400 \, \text{C}} \]
### Step 4: Calculate the charge for the second scenario
In the second scenario, we have:
- Current \( I_2 = 1.5 \, \text{A} \)
- Time \( t_2 = 1 \, \text{h} = 3600 \, \text{s} \)
Now, we can calculate the total charge \( Q_2 \):
\[ Q_2 = I_2 \cdot t_2 = 1.5 \, \text{A} \cdot 3600 \, \text{s} = 5400 \, \text{C} \]
### Step 5: Determine the mass deposited in the second scenario
Now we can use the same constant \( k \) to find the mass deposited in the second scenario:
Using the relationship \( m = k \cdot Q_2 \):
Since we already calculated \( Q_2 = 5400 \, \text{C} \) and we know \( k = \frac{2 \, \text{g}}{5400 \, \text{C}} \):
\[ m = \left(\frac{2 \, \text{g}}{5400 \, \text{C}}\right) \cdot 5400 \, \text{C} = 2 \, \text{g} \]
### Conclusion: Final Answer
Thus, the quantity of the same metal that would be deposited by the current of 1.5 A flowing for 1 hour is **2g**.
### Explanation of Other Options
- **Option B (6g)**: This option assumes that the mass deposited would be three times the original amount due to the increase in current. However, the time is also a factor, and in this case, the total charge remains the same.
- **Option C (10g)**: This option suggests an even larger increase in mass, which is incorrect as it does not take into account the time factor correctly.
- **Option D (18g)**: This option is also incorrect as it assumes a linear increase without considering the time duration properly.
### Revision Summary
- Faraday's laws of electrolysis relate mass deposited to the charge passed.
- The charge \( Q \) is calculated using \( Q = I \cdot t \).
- The mass deposited is directly proportional to the charge passed.
- In this case, the mass deposited remains the same (2g) despite the increase in current because the total charge is unchanged.