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The P-Block Elements

Question
CBSEENCH11007287
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Write a short note on borax bead test.

Solution
This test is meant for detecting the coloured cations. When borax is heated on a platinum loop it swells up into a white porous mass first which on subsequent heating melts into a shining transparent glass bead (B2O3).
Na subscript 2 straight B subscript 4 straight O subscript 7. space stack 10 straight H subscript 2 straight O with Borax below space space rightwards arrow with Heat on top space space Na subscript 2 straight B subscript 4 straight O subscript 7 space plus space 10 straight H subscript 2 straight O
Na subscript 2 straight B subscript 4 straight O subscript 7 space rightwards arrow with Heat on top space stack 2 NaBO subscript 2 space plus space straight B subscript 2 straight O subscript 3 with left parenthesis Borax space bead right parenthesis below
When this glass bead is heated with coloured compounds, a characteristic colour of metaborate is formed.
      CuSO subscript 4 space rightwards arrow with Heat on top space CuO space plus space SO subscript 3 CuO space plus stack space straight B subscript 2 straight O subscript 3 space rightwards arrow space space Cu left parenthesis BO subscript 2 right parenthesis subscript 2 with Cupric space metaborate left parenthesis Bluish space green right parenthesis below stack Cr subscript 2 straight O subscript 3 with Chromium space oxide below space plus space 3 straight B subscript 2 straight O subscript 3 space space space rightwards arrow space space stack 2 Cr left parenthesis BO subscript 2 right parenthesis subscript 3 with Chromium space metaborate space left parenthesis green right parenthesis below space space stack NiO space space with Nickel space oxide below space plus space space space straight B subscript 2 straight O subscript 3 space space space rightwards arrow space space space stack Ni left parenthesis BO subscript 2 right parenthesis subscript 2 with Nickel space metaborate space left parenthesis green right parenthesis below
However, in a reducing flame, a different colour is obtained. 
         2 Cu left parenthesis BO subscript 2 right parenthesis subscript 2 space plus space straight C space space rightwards arrow space space space 2 CuBO subscript 2 space plus straight B subscript 2 straight O subscript 3 space plus space CO space 2 CuBO subscript 2 space plus space straight C space rightwards arrow space space space stack 2 Cu space plus space straight B subscript 2 straight O subscript 3 space plus space CO with stack Metallic space copper with left parenthesis red space colour right parenthesis below below

Some More Questions From The p-Block Elements Chapter

Which is the hardest compound of boron?

What is inorganic benzene? Write its formula. 

Name a hydride of boron which is used as reducing agent in organic chemistry. 

Does a molecule of BH3 exist?

What is relative stability of +1 oxidation state in group 13.

Are all the B-H bonds in diborane equivalent?

What is tincal ?

What is tau or banana bond?

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