`Na_(2) B_(4) O_(7) overset(740^(@) C)underset(Delta)(to) underset("Transparent")ubrace(underset(X" " + " "Y)(2Na BO_(2) + B_(2) O_(2)))`
`Z + CuO(s) to underset("Blue Bead")ubrace(Cu(BO_(2))_(2))`
The Z will be

Options

A. X
B. Y
C. Mixture of X & Y in 2: 1 ratio
D. Mixture of X & Y in 1 : 2 ratio

Answer

To determine the compound Z in the given reaction, we need to analyze the information provided step by step.

### Step 1: Identify the Reaction
The reaction involves the heating of sodium tetraborate (Na₂B₄O₇) at 740°C, which decomposes into sodium metaborate (NaBO₂) and diboron trioxide (B₂O₃).

### Step 2: Write the Decomposition Reaction
The decomposition can be represented as:
\[ \text{Na}_2\text{B}_4\text{O}_7 \xrightarrow{740^\circ C} 2\text{NaBO}_2 + \text{B}_2\text{O}_3 \]
Here, we identify:
- X = NaBO₂ (sodium metaborate)
- Y = B₂O₃ (diboron trioxide)

### Step 3: Analyze the Reaction of Z with CuO
Next, we need to find out what Z is when it reacts with copper oxide (CuO) to form copper metaborate, which is represented as:
\[ \text{Z} + \text{CuO} \rightarrow \text{Cu(B(OH)₂)}_2 \]
This indicates that Z must be a compound that can react with CuO to produce Cu(B(OH)₂)₂.

### Step 4: Determine the Possible Candidates for Z
From the previous steps, we know:
- X (sodium metaborate) cannot be Z because sodium is more reactive than copper and will not be replaced.
- Y (diboron trioxide) can react with CuO to form copper metaborate.

### Step 5: Conclusion
Thus, the compound Z is:
\[ \text{Z} = \text{B}_2\text{O}_3 \]
Therefore, the correct answer is Y (diboron trioxide).

### Final Answer
The compound Z will be B₂O₃.

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