JAMB - Chemistry (1981 - No. 35)
5cm3 of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95g of solid salt. The solubility of sodium chloride at 30°C?
(Na = 23, Cl = 35.5)
(Na = 23, Cl = 35.5)
5.00 mole dm3
5.67 mole dm3
6.00 mole dm3
6.67 mole dm3
7.00 mole dm3
Explanation
1.95 gms of NaCl dissolves in 5 cm solution at 30°C
Number of gm of solute required to dissolve in
100 gm = (1.950 x 100)/ (5 x 1) = 1.95 x 20 = 39.0
390 gms will dissolve in 1000 dm3
Solution
Solubility of NaCl at 30°C in
(dm3 is 390)/(Mol wt g NaCl) = 6.67 mol dm3
Number of gm of solute required to dissolve in
100 gm = (1.950 x 100)/ (5 x 1) = 1.95 x 20 = 39.0
390 gms will dissolve in 1000 dm3
Solution
Solubility of NaCl at 30°C in
(dm3 is 390)/(Mol wt g NaCl) = 6.67 mol dm3
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