Looking for classes? Ksquare Career Institute, Bengaluru →
25.3 g of sodium carbonate, $Na_2CO_3$, is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, $Na^+$, and carbonate ions, $CO_3^{2-}$, are respectively (Molar mass of $Na_2CO_3$ = 106 g $mol^{-1}$)
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
Detailed Solution
Moles of $Na_2CO_3$ = $\frac{25.3}{106} = 0.2387$ mol
Molarity of $Na_2CO_3$ = $\frac{0.2387}{250}\times1000 = 0.955$ M
Complete dissociation: $Na_2CO_3 \rightarrow 2Na^+ + CO_3^{2-}$
$[Na^+] = 2\times0.955 = 1.910$ M
$[CO_3^{2-}] = 0.955$ M
Molarity of $Na_2CO_3$ = $\frac{0.2387}{250}\times1000 = 0.955$ M
Complete dissociation: $Na_2CO_3 \rightarrow 2Na^+ + CO_3^{2-}$
$[Na^+] = 2\times0.955 = 1.910$ M
$[CO_3^{2-}] = 0.955$ M