Explain any four of the chemical properties of water.

Explanation

1. Amphoteric nature : Water can act both as acid and base. In the Bronsted sence it acts as an acid with `NH_(3)` and a base with `H_(2)S`
`H_(2)O(l) +NH_(3)(aq) ltimplies OH^(-)(aq) + NH_(4)^(+)(aq)`
`H_(2)O (l) + H_(2)S (aq) ltimplies H_(3)O^(+)(aq) + HS^(-)(aq)`
(2). Reaction with Metals : Water reacts with metals liberating hydrogen. Here water is reduced to hydrogen and metals is oxidised
`2Na + 2H_(2)O rarr 2NaOH + H_(2)`
(3) HYdrolysis reaction: Several ionic and convalent compounds hydrolyse in water.
`P_(4)O_(10) + 6H_(2)O to 4H_(3)PO_(4)`
`SiCl_(4) + 2H_(2)O rarr SiO_(2) + 4HCl`
(4) Hydrates formation: When several salts crystalysed as hydrated salts
Eg: (i) `[Cr(H_(2)O_(6)]Cl_(3)` - coordinate water
(ii) `BaCl_(2).2H_(2)O` - Lattice water
(iii) `[Cu (H_(2)O)_(4)]SO_(4). H_(2)O`. The `H_(2)O` molecule outside the coordination sphere is hydrogen bonded water.