Question

An aqueous solution contains 0.3 M Cl'and 0.4 MF: A chemist wishes to do a fractional precipitation experiment in which he slowly adds Pb2+, which can form ppts of PbCl2(s) [K sp = 1.6 x 10-6] and PbF, (s) [Ksp = 7.1 x 10-7]. Which of the following is entirely correct? Pb2+ 0.3 M cl- 0.4M F- Cl precipitates first when [Pb2+] = 1.8 x 10-4 M. OF precipitates first when [Pb2+] = 1.0 x 10-4M. Cl precipitates first when [Pb2+] = 5.3 x 10-5 M F precipitates first when [Pb2+] = 1.1 x 10-6 M. OF precipitates first when [Pb2+] = 4.4 x 10-6 M. Question 30 Which of the following nuclear reactions requires a high temperature to start and continue? OB-emision 07 - emission O bombardment O fusion fission

Answer 1

af will precipitate first P6F2 has lower Kesp compared to Pb C₂ . Now, let [234] concentration during precipitation -X Pb 2+ + 2F P, F, [-] -0.4M [P02] [-] xx 0.16 .ksp OY, 7.1x101 Ok, x = 7.1x10-7 - 4.4 X10-6 0.16 Therefore, [Pb2+ 4.4810-6M Ans: F- precipitates first when [P62+] = 4.4x100M to overcome a question 30 Nuclear reaction that requires a high temperature start and continue are Fusion reactions where the high temperature gives the H atoms enough energy electrical repulsion between protous . Answer: Fusion reactions.