8/17/2019 C-B-N Inorganic Chemistry House

1/2

QUESTIONS AND PROBLEMS

1. If the O 3 contains only oxygen atoms, would it be polar? Explain your answer.2. Write complete balanced equations for the following processes.

(a) The reaction of magnesium boride with water (b) The combustion of B 2 H6

(c) The reaction of BCl 3 with C 2 H5 OH(d) The preparation of borazine(e) The reaction of H 3 BO3 with CH 3 COCl

3. Explain why the electron af nity of the O 2 molecule is 0.451 eV, whereas that of C 2 is 3.269 eV.4. Describe the bonding in the BO molecule.5. Would FB(OH) 2 be a stronger or weaker acid than boric acid? Explain your answer.6. On the basis of its structure, explain why boric acid is a weak acid that functions by complexing with OH . Draw the

structure for the product.7. If BF3 and B(CH 3 ) 3 were to react with the molecule

P :N:

What would you expect the products to be? Why?8. Pyridine cannot be used as the solvent when producing the adduct of ether with B(CH 3 ) 3 , but when producing the

pyridine adduct, ether can be used as the solvent. Explain this difference.9. Write equations to show the amphoteric behavior of Zn 2 þ in aqueous solutions.

10. Explain why a solution containing ferric chloride in water is acidic.11. In this chapter, the reaction between O 2 and PtF 6 was described. Would you expect N 2 to react in a similar way? Why

or why not?12. The ionization potential for O 2 is 12.06 eV and that for O 3 is 12.3 eV. If you were trying to obtain the O þ3 species,

what strategy would you follow?13. Determine the spectroscopic state for each of the following.

(a) B2 ; (b) O þ2 ; (c) C2

8/17/2019 C-B-N Inorganic Chemistry House

2/2

14. Consider the BF 3 and BH 3 molecules even though thelatter is not stable alone. One of these forms a stronger bond to(C 2 H5 )2 S and the other to (C 2 H5 ) 2 O. Explain how the molecules would preferentially bond.

15. Draw structures for the following. List all symmetry elements and determine the point group for each species.(a) ONF; (b) NCN 2 ; (c) OCN ; (d) C 3 O 2

16. Under certain conditions (such as in interstellar space), the OH radical has been observed. Construct the molecular orbital diagram for this species. Determine the bond order and determine what type of orbital contains the unpairedelectron.

17. Construct a molecular orbital energy-level diagram for the SO molecule and speculate on the nature of the bond andother characteristics of the molecule.

18. In BF3 , the Be F bond length is 130 pm, but in BF 4 , it is approximately 145 pm. Explain this difference in the B e Fbond lengths.

19. Would (C 2 H5 )3 N or (C 2 H5 )3 P react more energetically with BCl 3 if the reactants are dissolved in an inert solvent? Why?

20. Complete and balance the following.

(a) C2 H5 OH þ CaH 2 /(b) Alþ NaOH (in water) /(c) SiCl4 þ LiAlH4 /(d) BCl3 þ C2 H5 MgBr /(e) Fe2 O 3 þ Al /

21. Describe the major industrial use of oxygen, including equations if necessary.22. The process of adding two electrons to an oxygen atom,

Oð g Þ þ 2 e / O2 ð g Þ

absorbs 652 kJ mol 1 . Why are there so many ionic oxides?23. Write balanced equations to show the difference between methanides and acetylides in reacting with water.24. When CO bonds to BH 3 , how does it bond?25. Explain why BF3 is a weaker acid than BCl 3 .26. Write balanced equations for each of the following processes:

(a) preparation of B 3 N3 H6(b) preparation of (C 2 H5 )BH2(c) preparation of NaBH 4(d) combustion of diborane(e) preparation of (C 6 H5 )3 B

27. Describe the process by which H 2 O 2 is prepared.28. Heating many solid carbonates leads to decomposition. What products are obtained? Suppose CaCS 3 were heated

strongly. What would happen?29. Consider a 1 ion that contains one atom each of C, S, and P. Draw the correct structure and explain why any other

arrangements of atoms are unlikely.30. Write complete balanced equations to show the following processes.

(a) the reaction of BaO with SO 3(b) the preparation of calcium cyanamide(c) the oxidation of potassium cyanide with H 2 O 2(d) the preparation of hydrogen selenide

31. The Hþ3 ion has a trigonal planar structure. Rationalize this structure in terms of electron density within the structure.If one, two, or three H 2 molecules add to the H þ3 ion, where and how would they bond? Sketch these structures.