Question

which of the following is a carbohydrate? (circle the carbohydrate(s))
a. nh₃ b. co₂ c. c₂h₄o d. c₅h₁₀o₅ e. c₃h₈o₃

Explanation:

Step1: Recall the general formula of carbohydrates

The general formula of carbohydrates is \(C_n(H_2O)_m\), which means the ratio of hydrogen to oxygen is \(2:1\).

Step2: Analyze each option

• Option a: \(NH_3\) contains nitrogen, not in the form of \(C_n(H_2O)_m\), so it is not a carbohydrate.
• Option b: \(CO_2\) contains no hydrogen in the \(2:1\) ratio with oxygen (in terms of carbohydrate - like formula), so it is not a carbohydrate.
• Option c: \(C_2H_4O\), if we assume \(n = 2\) and try to fit into \(C_n(H_2O)_m\), for \(C_2(H_2O)_m\), if \(n=2\), then for \(H_4O\), \(m = 2\) (since \(H_2O\times2=H_4O_2\)), but here we have \(C_2H_4O\) (not \(C_2H_4O_2\)), so it is not a carbohydrate.
• Option d: \(C_5H_{10}O_5\), we can rewrite it as \(C_5(H_2O)_5\) (because \(H_{10}O_5=(H_2O)_5\)), which follows the general formula \(C_n(H_2O)_m\) (\(n = 5\), \(m = 5\)).
• Option e: \(C_3H_8O_3\), if we assume \(n = 3\) and try to fit into \(C_n(H_2O)_m\), for \(C_3(H_2O)_m\), if \(H_8O_3\), if \(m=\frac{8}{2}=4\) (from \(H\) part) but \(O\) is \(3\) (not \(4\)), so it is not a carbohydrate.

Answer:

d. \(C_5H_{10}O_5\)