Question

99 94. Gouta condition that results in joint swelling and pain- caused by the formation of sodium urate (NaCsH N4) crystals within tendons, cartilage, and ligaments. Sodium urate precipi tates out of blood plasma when uric acid levels become abnor- mally high. This could happen as a result of eating too many rich foods and consuming too much alcohol, which is why gout is sometimes referred to as the "disease of kings. If the sodium concentration in blood plasma is 0.140 M, and Kup for sodium urate is 5.76 X 10 8. what minimum concentration of urate would result in the precipitation of sodium urate? 100 101

Answer 1

Consider dissociation of sodium urate in water , NaC₅H₃N ₄ (s) Na ⁺ (aq) + C₅H₃N ₄ ^- (aq)

For above reaction, Ksp = [ Na ⁺ ] [C₅H₃N ₄ ^- ] = 5.76 10 ^-08

Therefore, [C₅H₃N ₄ ^- ] = K sp / [ Na ⁺ ] this is the maximum concentration of urate ions in the blood..

If [C₅H₃N ₄ ^- ] > K sp / [ Na ⁺ ] then NaC₅H₃N ₄ will precipitate.

From above fact, it is clear that K sp / [ Na ⁺ ] is minimum concentration of urate ion above which precipitation occurs.

Therefore, [C₅H₃N ₄ ^- ] min = K sp / [ Na ⁺ ] = 5.76 10 ^-08 / 0.140 = 4.11 10 ^-07 M

ANSWER : 4.11 10 ^-07 M