Give an account of the properties of washing soda.

Explanation

Chemical properties of `Na_(2)CO_(3)`:
(1) Action with acids : `CO_(2)` gas is liberated.
`Na_(2)CO_(3) + 2HCl to 2NaCl + H_(2)O + CO_(2)`
(2) Action with non-metal and their oxides: Sodium carbonate reacts with a mixture of S and `SO_(2)` and form Hypo (sodium thiosulphate)
`Na_(2)CO_(3) + SO_(2) + S to Na_(2)S_(2)O_(3) + CO_(3)`
(3) Action with `CO_(2)` : An aq. solution of sodium carbonate when saturated with `CO_(2)` gives ppt. of sodium bicarbonate.
`Na_(2)CO_(3) + H_(2)O + CO_(2) to 2NaHCO_(3)`
(4) Action with sillica : When fused with `SiO_(2)`, water glass is formed.
`Na_(2)CO_(3)+SiO_(2) to Na_(2)SiO_(3) + CO_(2)`
(5) Action with compounds: Insoluble metal carbonates are formed.
`MgCl_(2) + Na_(2)CO_(3) to MgCO_(3) + 2NaCl`
`ZnSO_(4) + Na_(2)CO_(3) to ZnCO_(3) + Na_(2)SO_(4)`
Aqueous `Na_(2)CO_(3)` solution is basic in nature. So methyl orange produces yellow colour in that solution.