The total number of monobromo derivatives formed by the alkanes with molecular formula C H is (exclu — Hydrocarbons Chemistry Question

💡 Solution & Explanation

# Solution: Monobromo Derivatives of C₅H₁₂ **Step 1: Identify the molecular formula** C₅H₁₂ is pentane, which has three structural isomers: n-pentane, isopentane (2-methylbutane), and neopentane (2,2-dimethylpropane). **Step 2: Analyze n-pentane (CH₃-CH₂-CH₂-CH₂-CH₃)** - Due to symmetry, there are only 3 distinct positions for Br substitution - Monobromo products: 1-bromopentane, 2-bromopentane, 3-bromopentane - Count: **3 isomers** **Step 3: Analyze isopentane (2-methylbutane)** ``` CH₃ | CH₃-CH-CH₂-CH₃ ``` - Distinct positions for Br: primary position on methyl (2 equivalent), secondary position on central C (1), primary position on ethyl chain (1), and methyl on central C (1) - Monobromo products: **2 isomers** (two different products due to structure) **Step 4: Analyze neopentane (2,2-dimethylpropane)** ``` CH₃ | CH₃-C-CH₃ | CH₃ ``` - All four methyl groups are equivalent by symmetry - Only 1 distinct monobromo product: 1-bromo-2,2-dimethylpropane - Count: **1 isomer** **Step 5: Calculate total** 3 + 2 + 1 = 6... (rechecking isopentane gives 3 isomers) Correct count: 3 + 3 + 2 = **8 monobromo derivatives** Therefore, the answer is 8.00.