A: `La(OH)_(3)`, is less basic than `Lu(OH)_(3)`,
R: Basic character of hydroxides of lanthanoids increase on moving from `La^(+3)`to `Lu^(+3)`

Options

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)

Answer

To solve the problem, we need to analyze both the assertion and the reason provided in the question.

### Step 1: Understand the Assertion
The assertion states that La(OH)₃ is less basic than Lu(OH)₃. We need to evaluate whether this statement is true or false.

### Step 2: Evaluate the Basicity of Hydroxides
Basicity in hydroxides is influenced by the size of the cation. Generally, larger cations tend to form more basic hydroxides because they can stabilize the hydroxide ion (OH⁻) better.

### Step 3: Analyze the Size of Cations
In the lanthanide series, as we move from La³⁺ (lanthanum) to Lu³⁺ (lutetium), the size of the cation decreases due to lanthanide contraction. This means that La³⁺ is larger than Lu³⁺.

### Step 4: Relate Size to Basicity
Since La³⁺ is larger than Lu³⁺, La(OH)₃ should be more basic than Lu(OH)₃. Therefore, the assertion that La(OH)₃ is less basic than Lu(OH)₃ is incorrect.

### Step 5: Understand the Reason
The reason states that the basic character of hydroxides of lanthanides increases from La³⁺ to Lu³⁺. However, based on our analysis, the basic character actually decreases from La(OH)₃ to Lu(OH)₃ due to the decrease in cation size.

### Step 6: Conclusion
Both the assertion and the reason are incorrect. Thus, the correct answer is that both the assertion and the reason are false.

### Final Answer:
Both assertion and reason are false.

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