When zeolite (hydrated sodium aluminium silicate) is treated with hard water the sodium ions are exchanged with

Options

A. `H^(+)` ions
B. `Ca^(2+)` ions
C. `SO_(4)^(2)` ions
D. None of these

Explanation

The reagent is ` Ba C l _ 2 ` which imparts green colour to flame . ` BaCl _ 2 ` forms chromyl chloride (which is red in colour ), when treated with ` K _ 2 C r _ 2 O _ 7 ` and conc. ` H _ 2 SO _ 4 ` .
` 2 Ba C l _ 2 + K _ 2 Cr _ 2 O _ 7 + 3 H _ 2 SO _ 4 to `
` K _ 2 SO _ 4 + 2 Ba SO _ 4 + underset ("(red gas)") underset ( "Chromyl cloride") ( 2 Cr O _ 2 Cl _ 2 + 3 H _ 2 O `