Question

Complete combustion of a sample of a hydrocarbon on excess oxygen produces equimolar quantities of carbon dioxide and water. Which of the following could be the molecular formula of the compound?

A. C2H2
B.C2H6
C.C4H8
D.C6H6

Answer 1

The correct molecular formula of the hydrocarbon producing equimolar quantities of CO2 and H2O upon combustion is option B, C2H6, as it has twice as many hydrogen atoms as carbon atoms, resulting in a balanced production of CO2 and H2O.

Step-by-step explanation:

The student is asking about the molecular formula of a hydrocarbon that produces equimolar quantities of carbon dioxide (CO2) and water (H2O) upon complete combustion. We know that hydrocarbons combust with oxygen to yield CO2 and H2O. A hydrocarbon producing equimolar amounts of CO2 and H2O indicates that the number of hydrogen atoms in the hydrocarbon is twice the number of carbon atoms.

Considering the options provided:

• A. C2H2
• B. C2H6 - Correct, as it has twice as many hydrogen atoms as carbon atoms.
• C. C4H8
• D. C6H6

The formula C2H6 (option B) is the correct choice because it will produce one molecule of CO2 and one molecule of H2O for each molecule of C2H6 burned in excess oxygen.

Answer 2

C. C4H8 Given that the number of moles of CO2 and H2O produced from the combustion are equal, that means for every carbon atom, there are 2 hydrogen atoms because CO2 has only 1 carbon atom and H2O has 2 hydrogen atoms. So let's look at the available choices and see which one is correct. A. C2H2 This is a 1 to 1 ratio of carbon to hydrogen. Wrong answer. B. C2H6 This is a 1 to 3 ratio of carbon to hydrogen. Wrong answer. C. C4H8 This is a 1 to 2 ratio of carbon to hydrogen. Correct answer. D. C6H6 This is a 1 to 1 ratio of carbon to hydrogen. Wrong answer.