1. which formula represents an alkane? a) c₂h₂ b) c₂h₄ c) c₃h₄ d) c₃h₈\n2. which hydrocarbon is saturated…

Explanation:

Step1: Recall alkane formula

The general formula for alkanes is $C_nH_{2n + 2}$.

Step2: Analyze question 1

For option A: $C_2H_2$, $n = 2$, $2n+2=2\times2 + 2=6\neq2$, not an alkane. For option B: $C_2H_4$, $n = 2$, $2n + 2=6\neq4$, not an alkane. For option C: $C_3H_4$, $n = 3$, $2n+2=8\neq4$, not an alkane. For option D: $C_3H_8$, $n = 3$, $2n+2=2\times3+2 = 8$, it is an alkane.

Step3: Recall saturated hydrocarbon concept

Saturated hydrocarbons are alkanes with the formula $C_nH_{2n + 2}$. Analyze question 2. For option A: $C_2H_2$ is an alkyne. For option B: $C_3H_4$ is an alkyne. For option C: $C_4H_6$ is an alkyne. For option D: $C_4H_{10}$, $n = 4$, $2n+2=10$, it is a saturated hydrocarbon (alkane).

Step4: Recall homologous - series concept

Alkanes form a homologous series with the general formula $C_nH_{2n + 2}$. $C_3H_8$ is an alkane. Analyze question 3. Option A: $CH_4$ is an alkane ($n = 1$, $2n+2=4$), belongs to the same homologous series as $C_3H_8$. Option B: $C_4H_8$ is an alkene ($C_nH_{2n}$). Option C: $C_5H_8$ is an alkyne ($C_nH_{2n - 2}$). Option D: $C_5H_{10}$ is an alkene.

Step5: Recall unsaturated hydrocarbon concept

Unsaturated hydrocarbons include alkenes ($C_nH_{2n}$) and alkynes ($C_nH_{2n - 2}$). Analyze question 4. Option A: $C_2H_4$, $n = 2$, follows the $C_nH_{2n}$ formula for alkenes, is an unsaturated hydrocarbon. Option B: $C_3H_8$ is an alkane (saturated). Option C: $C_4H_{10}$ is an alkane (saturated). Option D: $C_5H_{12}$ is an alkane (saturated).

Answer:

1. D. $C_3H_8$
2. D. $C_4H_{10}$
3. A. $CH_4$
4. A. $C_2H_4$