Question

What pH is needed to produce this value of Q if the concentration and pressure values are

[Br2]=3.00×10−4M , [Br−]=12.60M , [SO42−]=9.25M , and, PSO2=2.75×10−5atm ? Q = 2.3×10−26

SO42−(aq)+4H+(aq)+2Br−(aq)⇌Br2(aq)+SO2(g)+2H2O(l)

<Ch 20c (20.5-20.6) Tutorials (free energy, redox rxns, nonstandard cell potentials) + The Nernst Equation and pH Correct The reaction quotient is Q = 2.3 x 10-26 For any Q value less than this, E will be positive and therefore the reaction will favor products. Part B What pH is needed to produce this value of Q if the concentration and pressure values are · Br2] = 3.00 x 10-4 M, Br-] = 12.60M, · [SO42- ] = 9.25M , and • Pso, = 2.75 x 10-5 atm ? Express your answer numerically to two decimal places. ► View Available Hint(s) IVO AQ R o 2 ? pH = Submit Previous Answers Request Answer

Answer 1

The reaction is 5042 aq) + 4 H+ (aq) + 2 Br- (aq) = Brą (aq) + SO2 (g) + 2 H20 (1) The reaction quotient is = 2.3x10-26 [Br]]Pso2 2 150, 2 ][H*]*[Br-12 [Br;]* Pso, [H*J* = [SO,?][Br -] 2.3x10-26 [H+14 - _(3.00x104)(2.75x10-5) -= 2.44255 x 1014 (9.25)×(12.60) x (2.3x10-20) [H"]=(2.44255*104)*4 = 3953.3096 pH = -log[H+]=- log (3953.3096)=-3.60