A precipitate forms when a solution that is 0.10 M in Cu2+, Pb2+, ...

[ereecah]

A precipitate forms when a solution that is 0.10 M in Cu²⁺, Pb²⁺, and Ni²⁺ is saturated with H₂S and adjusted to pH = 1. What sulfides are present in the precipitate?
  H₂S = 0.10 M; for H₂S, K_a1  K_a2 = 1.1  10²⁴
  K_sp: CuS = 8.5  10⁴⁵, PbS = 7.0  10²⁹, NiS = 3.0  10²¹
   
  a.
  CuS, PbS, and NiS
   
  b.
  PbS and NiS
   
  c.
  NiS
   
  d.
  CuS and PbS
   
  e.
  CuS

Question 2

The concentration of Mg²⁺ in seawater is 0.052 M. At what pH will 99 of the Mg²⁺ be precipitated as the hydroxide? K_sp for Mg(OH)₂ = 8.9  10¹²
   
  a.
  8.35
   
  b.
  9.22
   
  c.
  6.50
   
  d.
  10.12
   
  e.
  4.86

Question 3

If 30 mL of 5.0  10⁴ M Ca(NO₃)₂ are added to 70 mL of 2.0  10⁴ M NaF, will a precipitate occur? (K_sp of CaF₂ = 4.0  10¹¹)
   
  a.
  No, because the ion product is greater than K_sp.
   
  b.
  Yes, because the ion product is less than K_sp.
   
  c.
  No, because the ion product is less than K_sp.
   
  d.
  Not enough information is given.
   
  e.
  Yes, because the ion product is greater than K_sp.

[kswal303]

Answer to Question 1

d

Answer to Question 2

d

Answer to Question 3

c

[ereecah]

Wow, this really help

[mochi09]

Great answer, keep it coming