{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Chapter 6: Electrochemistry" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 1, Page no: 180" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "\n", "# Variables\n", "T = 25 # C\n", "E = 0.296 # V\n", "Cu = 0.015 # M\n", "\n", "# Solution\n", "Eo = E - 0.0296 * log10(Cu)\n", "print \"The standard electrode potential is\", \"{:.3f}\".format(Eo), \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The standard electrode potential is 0.350 V\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 2, Page no: 180" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "\n", "# Variables\n", "T = 25 # C\n", "Cu = 0.1 # M\n", "Zn = 0.001 # M\n", "Eo = 1.1\n", "\n", "# Solution\n", "E = Eo + 0.0296 * log10(Cu / Zn)\n", "print \"The emf of Daniell cell is\", \"{:.4f}\".format(E), \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The emf of Daniell cell is 1.1592 V\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 3, Page no: 180" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "\n", "# Constant\n", "R = 8.314 # J / K\n", "F = 96500 # C / mol\n", "\n", "# Variables\n", "Cu = 0.15 # M\n", "Eo = 0.34 # V\n", "T = 298 # K\n", "n = 2 # moles\n", "\n", "# Solution\n", "E = Eo + (2.303 * R * T) / (n * F) * log10(Cu)\n", "print \"The single electrode potential for copper metal is\", \"{:.4f}\".format(E),\n", "print \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The single electrode potential for copper metal is 0.3156 V\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 4, Page no: 181" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variable\n", "Eo_Cu = 0.3370 # Cu+2 -> Cu\n", "Eo_Zn = - 0.7630 # Zn -> Zn +2\n", "\n", "# Solution\n", "Eo_cell = Eo_Cu - Eo_Zn\n", "print \"Daniel cell is, Zn | Zn +2 || Cu+2 | Cu\"\n", "print \"Eo (cell) is\", Eo_cell, \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Daniel cell is, Zn | Zn +2 || Cu+2 | Cu\n", "Eo (cell) is 1.1 V\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 5, Page no: 181" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variable\n", "Eo_Cu = 0.3370 # Cu+2 -> Cu\n", "Eo_Cd = - 0.4003 # Cd -> Cd +2\n", "\n", "# Solution\n", "Eo_cell = Eo_Cu - Eo_Cd\n", "print \"Cell is, Cd | Cd +2 || Cu+2 | Cu\"\n", "print \"Eo (cell) is\", Eo_cell, \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Cell is, Cd | Cd +2 || Cu+2 | Cu\n", "Eo (cell) is 0.7373 V\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 6, Page no: 181" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Constant\n", "F = 96500 # C / mol\n", "\n", "# Variables\n", "n = 2\n", "T = 25 # C\n", "Eo_Ag = 0.80 # Ag+ / Ag\n", "Eo_Ni = - 0.24 # Ni+2 / Ni\n", "\n", "# Solution\n", "Eo_Cell = Eo_Ag - Eo_Ni\n", "print \"Standard free energy change,\"\n", "delta_Go = - n * F * Eo_Cell\n", "print delta_Go, \"J / mol\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Standard free energy change,\n", "-200720.0 J / mol\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 7, Page no: 181" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Solution\n", "print \"-------------------------\"\n", "print \"Reduction half reaction:\",\n", "print \"2Fe+3 + 2e- --> 2Fe+2\"\n", "print \"Oxidation half reaction:\",\n", "print \"Fe - 2e- --> Fe+2\"\n", "print \"Overall cell reaction :\",\n", "print \"2Fe+3 + Fe --> 3Fe+2\"\n", "\n", "print \"-------------------------\"\n", "print \"Reduction half reaction:\",\n", "print \"Hg+2 + 2e- --> Hg\"\n", "print \"Oxidation half reaction:\",\n", "print \"Zn - 2e- --> Zn+2\"\n", "print \"Overall cell reaction :\",\n", "print \"Hg+2 + Zn --> Hg + Zn+2\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "-------------------------\n", "Reduction half reaction: 2Fe+3 + 2e- --> 2Fe+2\n", "Oxidation half reaction: Fe - 2e- --> Fe+2\n", "Overall cell reaction : 2Fe+3 + Fe --> 3Fe+2\n", "-------------------------\n", "Reduction half reaction: Hg+2 + 2e- --> Hg\n", "Oxidation half reaction: Zn - 2e- --> Zn+2\n", "Overall cell reaction : Hg+2 + Zn --> Hg + Zn+2\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 8, Page no: 181" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Constant\n", "F = 96500 # C / mol\n", "\n", "# Variables\n", "E1o = - 2.48 # V\n", "E2o = 1.61 # V\n", "\n", "# Solution\n", "delta_G1 = - 3 * F * (- 2.48)\n", "delta_G2 = - 1 * F * 1.61\n", "print \"delta_G3 = delta_G1 + delta_G2\"\n", "print \"delta_G3 = - 4 * F * E3o\"\n", "E3o = (delta_G1 + delta_G2) / (- 4 * F)\n", "print \"The reduction potential for the half-cell Pt/Ce, Ce+4\",\n", "print \"is\", \"{:.4f}\".format(E3o), \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "delta_G3 = delta_G1 + delta_G2\n", "delta_G3 = - 4 * F * E3o\n", "The reduction potential for the half-cell Pt/Ce, Ce+4 is -1.4575 V\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 9, Page no: 182" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Solution\n", "print \"Anodic half reaction :\",\n", "print \" Cd --> Cd+2 + 2e-\"\n", "print \"Cathodic half reaction :\",\n", "print \"2H+ + 2e- --> H2\"\n", "print \"-\" * 50\n", "print \"Overall cell reaction :\",\n", "print \"Cd + 2H+ <--> Cd+2 + H2\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Anodic half reaction : Cd --> Cd+2 + 2e-\n", "Cathodic half reaction : 2H+ + 2e- --> H2\n", "--------------------------------------------------\n", "Overall cell reaction : Cd + 2H+ <--> Cd+2 + H2\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 10, Page no: 182" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "\n", "# Variables\n", "T = 25 # C\n", "Cu = 0.1 # M\n", "Zn = 0.001 # M\n", "Eo = 1.1 # V\n", "\n", "# Solution\n", "print \"Zn(s) | Zn+2 (0.001M) || Cu+2(0.1M) | Cu(s)\"\n", "Ecell = Eo + 0.0592 / 2 * log10(Cu / Zn)\n", "print \"The emf of a Daniell cell is\", \"{:.4f}\".format(Ecell), \"V\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Zn(s) | Zn+2 (0.001M) || Cu+2(0.1M) | Cu(s)\n", "The emf of a Daniell cell is 1.1592 V\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 11, Page no: 182" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "\n", "# Variables\n", "pH = 7 # O2\n", "Eo = 1.229 # V\n", "pO2 = 0.20 # bar\n", "\n", "# Solution\n", "print \"Nearnst's equation at 25C is,\"\n", "print \"E = Eo - (0.0592 / 2) * log(1 / ([H+]^2 * [pO2]^ (1/2)))\"\n", "E = Eo - (0.0592 / 2) * log10(1.0 / (((10 ** (- 7)) ** 2) * (pO2 ** (1 / 2.0))))\n", "print \"The reduction potential for the reduction is\",\n", "print \"{:.3f}\".format(E), \"V\"\n", "# descrepency due to calculation error in the book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Nearnst's equation at 25C is,\n", "E = Eo - (0.0592 / 2) * log(1 / ([H+]^2 * [pO2]^ (1/2)))\n", "The reduction potential for the reduction is 0.804 V\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 12, Page no: 183" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "E_KCl = 0.2415 # V\n", "E_cell = 0.445 # V\n", "\n", "\n", "# Solution\n", "print \"Emf of the cell is\"\n", "print \"At 25C,\"\n", "print \"E = Er - El = Eref - ((RT)/ F) * ln H+\"\n", "pH = (E_cell - E_KCl) / 0.059\n", "\n", "Eo_cell = - 0.8277 # V\n", "print \"Thus, equilibrium constant for the reaction\"\n", "print \"\\t 2H2O --> H3O+ + OH- may be calculated as\"\n", "K = 10 ** (Eo_cell / 0.0591)\n", "print \"K =\", \"{:.0e}\".format(K)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Emf of the cell is\n", "At 25C,\n", "E = Er - El = Eref - ((RT)/ F) * ln H+\n", "Thus, equilibrium constant for the reaction\n", "\t 2H2O --> H3O+ + OH- may be calculated as\n", "K = 1e-14\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 13, Page no: 183" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "EoSn = 0.15 # V\n", "EoCr = - 0.74 # V\n", "\n", "# Solution\n", "print \"3Sn+4 + 2Cr --> 3Sn+2 + 2Cr+3\"\n", "Eo_cell = EoSn - EoCr\n", "n = 6\n", "K = 10 ** (n * Eo_cell / 0.0591)\n", "print \"The equillibrium constant for th reaction is\", \"{:.2e}\".format(K)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "3Sn+4 + 2Cr --> 3Sn+2 + 2Cr+3\n", "The equillibrium constant for th reaction is 2.27e+90\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 14, Page no: 184" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "T = 25 # C\n", "Eo = - 0.8277 # V\n", "\n", "# Solution\n", "print \"The reversible reaction,\"\n", "print \"2H2O <--> H3O+ + OH-\"\n", "print \"May be divided into two parts.\"\n", "print \"2H2O + e- --> 1/2 H2 + OH- (cathode) Eo = -0.8277 V\"\n", "print \"H2O + 1/2 H2 --> H3O+ + e- (anode) Eo = 0\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The reversible reaction,\n", "2H2O <--> H3O+ + OH-\n", "May be divided into two parts.\n", "2H2O + e- --> 1/2 H2 + OH- (cathode) Eo = -0.8277 V\n", "H2O + 1/2 H2 --> H3O+ + e- (anode) Eo = 0\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem: 15, Page no: 184" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "E = 0.4 # V\n", "\n", "# Solution\n", "print \"The cell is Pt(H2) | H+, pH2 = 1 atm\"\n", "print \"The cell reaction is\"\n", "print \"1/2 H2 --> H+ + e-\"\n", "pH = E / 0.0591\n", "print \"pH =\", \"{:.3f}\".format(pH)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The cell is Pt(H2) | H+, pH2 = 1 atm\n", "The cell reaction is\n", "1/2 H2 --> H+ + e-\n", "pH = 6.768\n" ] } ], "prompt_number": 4 } ], "metadata": {} } ] }