25.3 g of sodium carbonate, Na2CO3 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, CO32- are respectively (Molar mass of Na2CO3 = 106 g mol-1)
- 0.955 M and 1.910 M
- 1.910 M and 0.955 M
- 1.90 M and 1.910 M
- 0.477 M and 0.477 M
Answer
(2) 1.910 M and 0.955 M
Solution
Moles of Na2CO3 = 25.3106 = 0.2387 mol
Molarity of Na2CO3 = 0.2387 1000250 = 0.955 M
Na2CO3 2Na+ + CO32-
∴ [Na+] = 2 0.955 = 1.910 M
and [ CO32-] = 0.955 M
Answer: (2)