Which molecule listed below has a polar covalent bond?

Question:

  1. Which molecule listed below has a polar covalent bond?
    A) NaCl
    B) H20
    C) H2
    D) all of the compounds
    E) none of the compounds
  2. Which of the following statements is TRUE for the covalent molecule HCl?
    A) Chlorine is more electronegative and the shared electron pair is likely to be found on the hydrogen
    B) Chlorine is more electronegative and the shared electron pair is likely to be found on the chlorine atom.
    C) Hydrogen is more electronegative and the shared electron pair is likely to be found on the hydrogen atom
    D) Hydrogen is more electronegative and the shared electron pair is likely to be found on the chlorine atom
    E) none of the above
  3. The electronegativity value for Nis 3.0 and that for is 3.5. Based on these values, which of the following statements is TRUE about the compound NO?
    A) NO is an ionic compound
    B) NO is a nonpolar covalent compound,
    C) NO is a polar covalent compound.
    D) There is not enough information to determine the nature of NO.
    E) None of the above statements is true.
  4. Consider the following electronegativity values: H-21.-3.0. F = 4.0 Which molecule below would you expect to have the more polar bond?
    A) H2
    B) Cl2
    C)F2
    D) HCI
    E) HF
  5. Which one of the following aqueous solutions has the highest concentration?
    A) 0.1 MABrs.
    B) 0.2 M CaCl2.
    C) 0.2 M KNO:.
    D) 0.3 M C6H12O6,
    E) 0.1 M Al(SO4)3.
  6. How much water would you ADD to 175 ml of 6.00 M hydrochloric acid to prepare a 2.00 M solution of this acid?
    A) 525 ml
    B) 350 ml
    C) 58.3 mL
    D) 700 ml
    E) none of the above

Answer:

  1. H2O has a polar covelent bond (Option B)
  2. Because Chlorine is more electronegative, the electron is likely to be on Chlorine atom (Option B)
  3. The difference in electronegative is 3.5 – 3.0 = 0.5. Thus, the bond is polar but covalent. Ionic bonds need electronegativity difference of more than 2. Answer will be polar covalent (Option C)
  4. Higher the electronegativity difference, more ionic will be the bond. H has the lowest electronegativity and F the highest. Thus, HF will be most ionic (Option E)
  5. 0.1 M of Al2(SO4)3 can dissociate into 0.5 M ions. C6H12O6 does not dissociate., 0.1 M AlBr3 will have 0.4 M concentration, 0.2 M CaCl2 has 0.2 x 3 = 0.6 M and 0.2 M KNO3 has 0.4 M ions.

Thus, the answer will be 0.2 M CaCl2 (Option B)

  1. Molarity needs to be made 1/3rd. Thus volume needs to be tripled to 175 mL x 3 = 525 mL. Water needed = 525 mL -175 mL = 350 mL (Option B)

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