Ch.22 - The Main Group Elements
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- In the early 1960s, krypton was found to react with fluorine gas in an electrical discharge tube at -183 °C. The compound formed was KrF2. What are the oxidation states of Kr and F in this compound? What is the electron-dot structure and geometry?
Problem 158
- What is the electron-dot structure and geometry of XeO3?
Problem 159
- Of ammonia, hydrazine, and hydroxylamine, which reacts to the greatest extent with the weak acid HNO₂? Consult Appendix C for equilibrium constants.
Problem 161
- Consider phosphorous acid, a polyprotic acid with the formula H3PO3. (a) Draw two plausible structures for H3PO3. For each one, predict the shape of the pH titration curve for the titration of H3PO3 (Ka1 = 1.0 * 10^-2) with aqueous NaOH. (b) For the structure with the H atoms in two different environments, calculate the pH at the first and second equivalence points, assuming that 30.00 mL of 0.1240 M H3PO3 (Ka2 = 2.6 * 10^-7) is titrated with 0.1000 M NaOH.
Problem 164
- A 5.00 g quantity of white phosphorus was burned in an excess of oxygen, and the product was dissolved in enough water to make 250.0 mL of solution. (b) What is the pH of the solution? (c) When the solution was treated with an excess of aqueous Ca(NO3)2, a white precipitate was obtained. Write a balanced equation for the reaction and calculate the mass of the precipitate in grams. (d) The precipitate in part (c) was removed, and the solution that remained was treated with an excess of zinc, yielding a colorless gas that was collected at 20 °C and 742 mm Hg. Identify the gas, and determine its volume.
Problem 166