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

Answer

3

Explanation

`M(Na_(2)CO_(3))=n_(Na_(2)CO_(3))/V_(mL)xx(1000 mL)/L`
`=(25.3 g Na_(2)CO_(3)//106 g Na_(2)CO_(3) mol^(-1))/(250 mL)xx(1000 mL)/L`
`=0.955 mol L^(-1)
Na_(2)CO_(3)(aq) rarr 2Na^(+)(aq)+CO_(3)^(2-)(aq)`
`1 mol 2 mol 1 mol`
Thus `M(Na^(+))=2M(Na_(2)CO_(3))=2(0.955 M)=1.910 M`
`M(CO_(3)^(2-))=M(Na_(2)CO_(3))`
`=0.955 M`