1.

`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(B)` is.A. `Na_(2)B_(4)O_(7)`B. `NaBO_(2)`C. `Na_(3)BO_(3)`D. `NaOH`

Answer» Correct Answer - A
`underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)N_(4)O_(7))+ 2CO_(2)`
`underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)`
`underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))`
`underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))`
`underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O`
`underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`.
`Na_(2)B_(4)O_(7)`.]


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