In borex bead test which compound is formed
- Ortho borate
- Meta borate
- Double oxide
- Tetra borate
The Correct Option is B
Solution and Explanation
The borax bead test is a qualitative analysis technique used to identify certain metal ions based on the color of the bead formed when a metal salt is heated with borax in the presence of a flame. The principle behind this test involves the transformation of borax into metaborate in a hot environment.
When borax (\text{Na}_2\text{B}_4\text{O}_7 \cdot 10 \text{H}_2\text{O}) is heated, it first loses its water of crystallization and then forms a glassy bead that consists primarily of metaborate ions. The balanced chemical transformation is as follows:
\text{Na}_2\text{B}_4\text{O}_7 \cdot 10 \text{H}_2\text{O} \rightarrow 2\text{NaBO}_2 + 4\text{B}_2\text{O}_3 + 10\text{H}_2\text{O}
In this reaction, the sodium metaborate (\text{NaBO}_2) is formed, which is the bead that combines with metal ions to give varied colors characteristic of different metal ions.
This indicates that Meta borate compounds are formed during the borax bead test. Therefore, among the options provided:
- Ortho borate is not formed in this test.
- Double oxide is a different compound not related to the borax bead test.
- Tetra borate refers to the borax itself in polyborate form before decomposition.
Thus, the correct answer is Meta borate as it denotes the formation of the compounds during the borax bead test, which is answered in the question.
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