Answer number 2 only. Please answer all the question in in number 2. EVALUATION (10 MINS)1. Balance the following redox reactions:a. CH4 + NO2 -> N2 + CO2 + H2O (oxidation number method)b. Zn + Cr2O,2- -> Zn2+ + Cr3+ (half-reaction method, in acidic medium)2. When silver metal, Ag, is exposed to hydrogen sulfide gas, H2S, it tarnishes.Is the reaction of Ag with H2S a redox reaction? How did you arrive at your answer? If your answer is yidentify the RA and OA.Evaluation1(Not Visible)34.(Needs Improvement)(Meets Expectations)(Ex

1. a. CH4 + NO2 = CO2 + N2 + H2O The oxidation number of C in CH4 and CO2 are -4 and +4…

EVALUATION (10 MINS) 1. Balance the following redox reactions: a. CH4 + NO2 -> N2 + CO2 + H2O (oxidation number method) b. Zn + Cr2O,2 2. When silver metal, Ag, is exposed to hydrogen sulfide gas, H2S, it tarnishes. Is the reaction of Ag with H2S a redox reaction? How did you arrive at your answer? If your answer is yo identify the RA and OA. -> Zn2+ + Cr³+ (half-reaction method, in acidic medium) Evaluation 1 (Not Visible) 4 (Needs Improvement) (Meets Expectations) (Ex

EVALUATION (10 MINS) 1. Balance the following redox reactions: a. CH4 + NO2 -> N2 + CO2 + H2O (oxidation number method) b. Zn + Cr2O,2 2. When silver metal, Ag, is exposed to hydrogen sulfide gas, H2S, it tarnishes. Is the reaction of Ag with H2S a redox reaction? How did you arrive at your answer? If your answer is yo identify the RA and OA. -> Zn2+ + Cr³+ (half-reaction method, in acidic medium) Evaluation 1 (Not Visible) 4 (Needs Improvement) (Meets Expectations) (Ex

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter22: Bulk Electrolysis: Electrogravimetry And Coulometry

Section: Chapter Questions

Problem 22.21QAP

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0.1724g of a mineral containing MnO₂ was dissolved and then treated with excess iodide according to the following unbalanced reaction: MnO2(s) + H+ → Mn²+ + I2 + H₂O The I₂ released was titrated with a solution of Na₂S2O3 0.07320 mol/L, requiring 14.65 mL to reach the point end of degree a) Determine the percentage of MnO₂ in the ore. b) When iodine solutions are used as titrants these are prepared by dissolving 1₂ in concentrated KI. Explain the reason for the need for KI in the preparation of these solutions?
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For Redox Analysis of Iron... ~0.02 M of potassium dichromate is prepared as titrant for dried unknown. ~.3 g of sample, 50ml of 6M HCl, 20mL SnCl2, 10 mL of saturated HgCl2 solution, 60 mL of 3M H2SO4, 15mL of concentrated H3PO4, 100mL DI water. HCl (+ heat in fumehood until samples dissolves), SnCl2 (added with pipet until solution changes from yellow to colorless/light green with 3 drops in excess), HgCl2 (after cooling), H2SO4, H3PO4, DI Water, is added to the sample solution with 8 drops of diphenylamine sulfonate indicator then titrated with the potassium dichromate to a violet blue endpoint. 1. What is the purpose of the phosphoric acid in this experiment? Please be specific. 2. How does the Diphenylamine sulfonate indicator work? What chemical reaction causes the color change? How is an indicator chosen in a redox reaction?
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