Identify correct statement from the following
i. `H_(3)BO_(3)` is a monobasic acid.
ii. The correct formula of borax is `Na_(2)[B_(4)O_(5)(OH)_(3)]8H_(2)O`.
iii. `NaBH_(4)` is a reducing agent.

Options

A. i,ii, iii
B. i, ii only
C. ii, iii only
D. i, iii only

Answer

B

Explanation

The explanations of given stataments are as follows :
(i) `H_(3)BO_(3)` is a monobasic acid because in aqueous solution, it coordinates with a molecule of water to form a hydrated species,
`B^(3+)` ion pulls the `sigma` - electron charge of corrdinated O-atom towards itself. The corrdinated oxtgen, in turn, pull the `sigma`- electrons of O-H bond of the attached water molecules towards itself. This facilities the removal of `H^(+)` ion from the O-H bond.
It can be written as follows :
`B(OH)_(3) + H_(2)O hArr [B(OH)_(4)]^(-) + H^(+)`
(ii) The correct formula for borax is `Na_(2)[B_(4)O_(7)].10H_(2)O`.
(iii) `NaBH_(4)` is a selective reducing agent for aldehydes, ketones and ester.
Thus, statements (i) and (iii) are correct.