13. 25.3g of sodium carbonate, Na,CO is dissolvedifin enough water to make 250 mL of solution. Isodium carbonate dissociates completely, molarconcentration of sodium ion. Nat and carbonateons, Co are respectively (Molar mass ofNa,cO, 106 g mol-1) [AIPMT (Prelims)-2010](1) 0.955 M and 1.910 M(2) 1.910 M and 0.955 M(3) 1.90 M and 1.910 M(4) 0.477 M and 0.477 M

13. 25.3g of sodium carbonate, Na,CO is dissolvedifin enough water to

1.	13. 25.3g of sodium carbonate, Na,CO is dissolvedifin enough water to make 250 mL of solution. Isodium carbonate dissociates completely, molarconcentration of sodium ion. Nat and carbonateons, Co are respectively (Molar mass ofNa,cO, 106 g mol-1) [AIPMT (Prelims)-2010](1) 0.955 M and 1.910 M(2) 1.910 M and 0.955 M(3) 1.90 M and 1.910 M(4) 0.477 M and 0.477 M
Answer» Moles of Na2CO3= mass/molar mass = 25.3/106 = 0.239 molesMolarity of Na2CO3solution = number of moles/ volume in lire = 0.239/0.25 (250ml = 0.25 L) = 0.955 MNow, 1 mole of Na2CO3contains 2 moles of Na+and 1 mole of CO32-ions.Therefore,Concentration of Na+= 2 x 0.955M = 1.91MConcentration of CO32-= 1 x 0.955M = 0.955M