A sparingly soluble salt $AB$ has $K_{s p} = 1.0 \times 1 0^{- 5}$ . It is dissolved in $0.002 M$ $NaA$ solution (fully dissociated). Solving without neglecting any term, its solubility (in $mol L^{- 1}$ ) is

Answer: A

Let solubility be

s

s (s + 0.002) = 1.0 \times 1 0^{- 5}

, i.e.

s^{2} + 0.002 s - 1 0^{- 5} = 0

s = [- 0.002 + (0.002)^{2} + 4 \times 1 0^{- 5}] /2 = 2.3 \times 1 0^{- 3} M

. The shortcut

K_{s p} /0.002

overestimates because

s

is not small compared with

0.002

A saturated solution of Mg(OH)2 (K_sp = 1.6 x 10^-11) with excess solid is at 298 K. Choose the correct statement(s). JEE Main level
AgNO3 is added gradually to a solution containing 0.010 M Cl^- and 0.010 M CrO4^2-. K_sp: AgCl = 1.8 x 10^-10, Ag2CrO4 = 2.0 x 10^-12. When ... JEE Advanced level
M^2+ (0.10 M) is to be removed from solution as M(OH)2 (K_sp = 2.5 x 10^-13) until only 0.1% of it remains. Using log 5 = 0.699, the minimum... JEE Advanced level
100 mL of 0.04 M MgCl2 is mixed with 100 mL of 0.20 M aqueous NH3 (K_b = 1.8 x 10^-5). Taking K_sp(Mg(OH)2) = 1.6 x 10^-11 and neglecting an... JEE Advanced level
A solution is 0.010 M in Mg^2+ and 0.10 M in NH3 (K_b = 1.8 x 10^-5). K_sp(Mg(OH)2) = 1.6 x 10^-11. Find the minimum mass of solid NH4Cl (mo... JEE Advanced level
AgNO3 is added gradually to a solution that is 0.050 M in Cl^- and 0.020 M in CrO4^2-. With K_sp(AgCl) = 1.8 x 10^-10 and K_sp(Ag2CrO4) = 2.... JEE Advanced level