The compound `Na_(2)CO_(3) . xH_(2)O` has 50% `H_(2)O` by mass. The value of “x” is

Options

A. 4
B. 5
C. 6
D. 7

Answer

C

Explanation

(i) `because` Molar mass of `Na_(2)CO_(3) = 106` unit
(23 x 2)+12+(3 x 16)
and `CO_(3)^(2-)` has two (-) charge
While two `Na^(+)` ions are involved,
(ii) Number of moles (per unit charge) = 50% of
`106 is 106//2 = 53 g`
`=53/18`
=2.94 mol
total mole of `H_(2)O=2xx2.94=5.89=6.00`