A and B are formed when borax, is dissolved in water. C and B are formed when borax is reacted with aqueous HCl solution. What are A and C respectively?

Options

A. NaCl, NaOH
B. NaOH, NaCl
C. `NaBO_(2),NaCl`
D. `NaOH,NaBO_(2)`

Answer

B

Explanation

The reaction of borax ` (Na_(2) B_(4) O_(7))` with water occurs as follows :
`Na_(2) B_(4) O_(7) + 7H_(2)O to underset(B)(4H_(3) BO_(3)) + underset(A) (2NaOH)`
While, borax reacts with HCl (dil) as follows:
`Na_(2) B_(4) O_(7) + 2HCl"(dil)" to 2NaCl + 4 [B(H_(2)O)(OH)_(3)]`
or
`Na_(2) B_(4) O_(7) + 2HCl + 9H_(2)O to underset((C))(2NaCl) + 4[ B(H_(2)O)(OH)_(3) ]`
or , ` Na_(2)B_(4)O_(7) + 2HCl.10H_(2)O to underset((B))(4H_(3) BO_(3))+ underset((C))(2NaCl) + 5H_(2)O`
Hence ,(A) = NaOH and (C) = NaCl
Hence , option (b) is the correct answer .