Question 1

Which of the following pairs of compounds are constitutional isomers?

Accepted Answer

C$$_2H$_6O ($$ethanol) and C$$_2H$_6O ($$dimethyl ether)

Question 2

Given the following resonance structures for the acetate ion (CH$$_3$$COO$$^-$$), which structure contributes more to the resonance hybrid?

Accepted Answer

The structure with both oxygens sharing the negative charge equally

Question 3

Which of the following bonds is expected to be the shortest?

Accepted Answer

$$\mathrm{C \equiv N} ($$triple bond)

Question 4

What is the hybridization and formal charge of the nitrogen atom in the ammonium ion ($$\mathrm{NH_4$^+}$$)?

Accepted Answer

sp$$^3$$ hybridized, formal charge = +1

Question 5

Consider the acid-base equilibrium: $$\mathrm{CH_3COOH + OH^- \rightleftharpoons CH_3COO^- + H_2O}. $$Which side of the equilibrium is favored?

Accepted Answer

Products, because water is a weaker base than hydroxide

Question 6

Which of the following is NOT a valid resonance structure for the nitrate ion ($$\mathrm{NO_3$^-}$$)?

Accepted Answer

A structure with all single bonds and a negative charge on the nitrogen

Question 7

Which statement about acetone ($$\mathrm{CH_3COCH_3}) is $$INCORRECT?

Accepted Answer

It contains a carboxylic acid functional group

Question 8

Rank the following compounds in order of increasing acidity: phenol, ethanol, acetic acid.

Accepted Answer

ethanol \u003c phenol \u003c acetic acid

Question 9

Which hydrogen is the most acidic in acetylacetone ($$\mathrm{CH_3COCH_2COCH_3}$$)?

Accepted Answer

The hydrogen on the central methylene carbon ($$\mathrm{CH_2$})$$

Question 10

Given the reaction: $$\mathrm{HCl + NH_3$ \rightarrow NH_4$^+ + Cl^-}$$, which statement is INCORRECT?

Accepted Answer

Cl$$^- is $$the conjugate acid of HCl

Question 11

Which functional group is present in the following molecule: $$\mathrm{CH_3CH_2COOH}$$?

Accepted Answer

Carboxylic acid

Question 12

What is the predominant intermolecular force in liquid methanol ($$\mathrm{CH_3OH}$$)?

Accepted Answer

Hydrogen bonding

Question 13

Rank the following compounds in order of increasing boiling point: methane, methanol, chloromethane.

Accepted Answer

methane \u003c chloromethane \u003c methanol

Question 14

Which of the following statements about water ($$\mathrm{H_2O}) is $$CORRECT?

Accepted Answer

The oxygen atom is sp$$^3$$ hybridized

Question 15

Which of the following pairs are resonance structures?

Accepted Answer

Two structures of benzene with alternating double bonds

Question 16

Which compound is expected to have the highest water solubility?

Accepted Answer

Acetic acid ($$\mathrm{CH_3COOH})$$

Question 17

Which of the following statements about the formal charge on the central atom in $$\mathrm{CO_2$} is $$correct?

Accepted Answer

The formal charge on carbon is 0

Question 18

Which of the following best describes the geometry around the nitrogen atom in ammonia ($$\mathrm{NH_3$}$$)?

Accepted Answer

Trigonal pyramidal

Question 19

Which of the following statements about the acidity of phenol is correct?

Accepted Answer

Phenol is more acidic than ethanol due to resonance stabilization of its conjugate base

Question 20

Which of the following best explains why the pKa of acetic acid ($$\mathrm{CH_3COOH}) is $$lower than that of ethanol ($$\mathrm{CH_3CH_2OH}$$)?

Accepted Answer

The conjugate base of acetic acid is resonance stabilized

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