`25.3 g` sodium carbonate, `Na_(2)CO_(3)`, was dissolved in enough water to make `250 mL` of solution. If sodium carbonate dissociates completely, molar concentration of `Na^(+)` and carbonate ions are respectively:

Options

A. 0.955 M and 1.910 M
B. 1.910 M and 0.955 M
C. 1.90 M and 1.910 M
D. 0.477 and 0.477 M

Answer

B

Explanation

Molarity `(M )=(wt)/(mol .wt.) (1000)/(vol (ml))`
`=(25.3)/(106)xx(1000)/(250)`
`=.955mol//L`of `Na_(2)CO_(3)`
and `Na_(2)CO_(3) to 2Na^(+)+CO_(3)^(-2)`
therefore`[Na^(+)]=2xx0.955=1.910M`
`[CO_(3)^(-2)]=0.955M`