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Borax [Na(2)B(4)O(7).10H(2)O] when heate...

Borax `[Na_(2)B_(4)O_(7).10H_(2)O]` when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate.
`{:(" Colour of the bead"," lon"),("(a) Blue green or light blue",Cu^(+2)),("(b) Yellow",Fe^(+2)or Fe^(+3)),("(c) Green",Cr^(+3)),("(d) Violet",Mn^(+2)),("(e) Dark blue",Co^(+2)),("(f) Brown",Ni^(+2)):}`
The colour of bead `Ni(BO_(2))_(2)` is

A

Green

B

Brown

C

Violet

D

Blue

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the color of the bead formed by nickel metaborate (NiBO₂) when borax is heated and reacted with nickel oxide, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding Borax**: - Borax is represented by the formula `Na₂B₄O₇·10H₂O`. When heated, it loses water and forms sodium tetraborate (`Na₂B₄O₇`). 2. **Formation of Boric Glass**: - Upon further heating, sodium tetraborate (`Na₂B₄O₇`) transforms into sodium metaborate (`NaBO₂`) and boric anhydride (`B₂O₃`), resulting in a glass-like bead known as boric glass or boric bead. 3. **Dipping the Bead in Metal Oxide**: - The hot boric bead is then dipped into a salt containing a transition metal oxide. In this case, we are focusing on nickel oxide (`NiO`). 4. **Reaction with Nickel Oxide**: - When the boric bead reacts with nickel oxide, it forms nickel metaborate, represented as `Ni(BO₂)₂`. 5. **Identifying the Color of the Bead**: - The characteristic colors produced by various transition metal ions when reacted with boric acid are given. For nickel ions (`Ni²⁺`), the color of the resulting bead (nickel metaborate) is specified as brown. 6. **Conclusion**: - Therefore, the color of the bead formed by nickel metaborate (`Ni(BO₂)₂`) is brown. ### Final Answer: The color of the bead Ni(BO₂)₂ is **brown**. ---
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Borax [Na_(2)B_(4)O_(7).10H_(2)O] when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. {:(" Colour of the bead"," lon"),("(a) Blue green or light blue",Cu^(+2)),("(b) Yellow",Fe^(+2)or Fe^(+3)),("(c) Green",Cr^(+3)),("(d) Violet",Mn^(+2)),("(e) Dark blue",Co^(+2)),("(f) Brown",Ni^(+2)):} Glassy bead is of

Borax [Na_(2)B_(4)O_(7).10H_(2)O] when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. {:(" Colour of the bead"," lon"),("(a) Blue green or light blue",Cu^(+2)),("(b) Yellow",Fe^(+2)or Fe^(+3)),("(c) Green",Cr^(+3)),("(d) Violet",Mn^(+2)),("(e) Dark blue",Co^(+2)),("(f) Brown",Ni^(+2)):} The flame used in Borax Bead test is

Borax [Na_(2)B_(4)O_(7).10H_(2)O] when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. {:(" Colour of the bead"," lon"),("(a) Blue green or light blue",Cu^(+2)),("(b) Yellow",Fe^(+2)or Fe^(+3)),("(c) Green",Cr^(+3)),("(d) Violet",Mn^(+2)),("(e) Dark blue",Co^(+2)),("(f) Brown",Ni^(+2)):} The hybridisation of B in Borax is

Borax Bead Test is carried out when the original mixture is coloured. It is done with the help of a cleam platinum wire on which a small loop is made at the end. When borax is heated on platinum wire loop transparent glass like bead is obtained. The hot bead is brought in contact with salt till it reacts with fused borax and colour is imparted to the bead. bead colour is noted. {:("Colour of the bead","Ion"),(1." Blue green",Cu^(2+)),(2." Yellow ",Fe^(3+)),(3." Green",Cr^(3+)),(4." Violet",Mn^(2+)),(5." Dark blue",Co^(2+)),(6." Brown",Ni^(2+)):} Q. Blue bead can be of:

Borax Bead Test is carried out when the original mixture is coloured. It is done with the help of a cleam platinum wire on which a small loop is made at the end. When borax is heated on platinum wire loop transparent glass like bead is obtained. The hot bead is brought in contact with salt till it reacts with fused borax and colour is imparted to the bead. bead colour is noted. {:("Colour of the bead","Ion"),(1." Blue green",Cu^(2+)),(2." Yellow ",Fe^(3+)),(3." Green",Cr^(3+)),(4." Violet",Mn^(2+)),(5." Dark blue",Co^(2+)),(6." Brown",Ni^(2+)):} Q. The flame used in Borax Bead Test is:

Borax Bead Test is carried out when the original mixture is coloured. It is done with the help of a cleam platinum wire on which a small loop is made at the end. When borax is heated on platinum wire loop transparent glass like bead is obtained. The hot bead is brought in contact with salt till it reacts with fused borax and colour is imparted to the bead. bead colour is noted. {:("Colour of the bead","Ion"),(1." Blue green",Cu^(2+)),(2." Yellow ",Fe^(3+)),(3." Green",Cr^(3+)),(4." Violet",Mn^(2+)),(5." Dark blue",Co^(2+)),(6." Brown",Ni^(2+)):} Q. Glassy bead of :

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