Question 1

Which of the following statements best explains why all four C-H bonds in methane ($$CH_4) $$are identical in energy and length?

Accepted Answer

Because the carbon atom in methane undergoes $$sp^3$$ hybridization, forming four equivalent hybrid orbitals.

Question 2

What is the bond angle in a molecule where the central atom is $$sp^2$$ hybridized?

Accepted Answer

$$120^\circ$$

Question 3

Which of the following molecules is predicted to be polar based on its Lewis structure and molecular geometry?

Accepted Answer

Methanol ($$CH_4O)$$

Question 4

How many sigma ($$\sigma) $$and pi ($$\pi) $$bonds are present in a molecule of ethylene ($$C_2H_4$$)?

Accepted Answer

5 $$\sigma$$, 1 $$\pi$$

Question 5

Which hybridization and geometry are associated with the carbon atom in acetylene ($$C_2H_2$$)?

Accepted Answer

$$sp$$, linear

Question 6

A molecule has a central atom with three sigma bonds and one lone pair. What is the expected hybridization and geometry of the central atom?

Accepted Answer

$$sp^3$$, trigonal pyramidal

Question 7

Which of the following best describes the difference between a sigma ($$\sigma) $$and a pi ($$\pi) $$bond?

Accepted Answer

A $$\sigma$$ bond is formed by head-on overlap of orbitals, while a $$\pi$$ bond is formed by side-to-side overlap of unhybridized $$p$$ orbitals.

Question 8

Given the Lewis structure for formaldehyde ($$H_2C=O$$), what is the hybridization of the carbon atom?

Accepted Answer

$$sp^2$$

Question 9

Which of the following is a correct step in determining the formal charge of an atom in a Lewis structure?

Accepted Answer

Subtract the number of lone pair electrons and the number of bonds from the atom's valence electrons.

Question 10

Which of the following molecules contains a carbon atom with $$sp^3$$ hybridization?

Accepted Answer

Methane ($$CH_4)$$

Question 11

A student draws the Lewis structure for $$C_2H_6O$$ and finds two possible structures. What is the relationship between these two structures?

Accepted Answer

They are structural (constitutional) isomers.

Question 12

Which of the following best describes the geometry and polarity of carbon dioxide ($$CO_2$$)?

Accepted Answer

Linear and nonpolar

Question 13

Which of the following statements about the hybridization of oxygen in water ($$H_2O) is $$correct?

Accepted Answer

Oxygen is $$sp^3$$ hybridized, resulting in a bent molecular geometry.

Question 14

Which of the following is a correct application of the octet rule when drawing Lewis structures for organic molecules?

Accepted Answer

Each carbon atom should have four bonds unless it carries a formal charge.

Question 15

Which of the following best explains why acetylene ($$C_2H_2) is $$used as a fuel in welding torches?

Accepted Answer

It burns at a very high temperature due to the energy stored in its triple bond.

Question 16

Which of the following is the correct formula to calculate the number of bonds in a Lewis structure, given the total electrons needed ($$e_O) $$and the total valence electrons ($$e_V$$)?

Accepted Answer

$$E = \frac{e_O - e_V}{2}$$

Question 17

Which of the following molecules has all its carbon atoms $$sp^2$$ hybridized and is nonpolar?

Accepted Answer

Benzene ($$C_6H_6)$$

Question 18

Which of the following steps is NOT part of the process for drawing a Lewis structure for an organic molecule?

Accepted Answer

Assigning hybridization before counting valence electrons.

Question 19

Which of the following best describes the relationship between molecular geometry and polarity?

Accepted Answer

A molecule is polar if the vector sum of its bond dipoles is not zero.

Hybridization, Lewis Structures, and Molecular Geometry in Organic Chemistry

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