See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Concept: Compounds that react with Na metal to evolve H2 gas must contain an active hydrogen bonded to an electronegative atom (O-H group). For C4H10O, the functional groups possible are alcohols (R-OH) and ethers (R-O-R). Only alcohols react with Na to release H2; ethers do not. Step 1: Determine the degree of unsaturation for C4H10O. Degree of unsaturation = (2×4 + 2 - 10)/2 = 0. So no rings or double bonds; the compound is saturated. Step 2: List all alcohol isomers of C4H10O (structures with -OH group), excluding stereoisomers. 1. 1-Butanol: CH3CH2CH2CH2OH (n-butyl alcohol) 2. 2-Butanol: CH3CH2CH(OH)CH3 (sec-butyl alcohol) 3. 2-Methyl-1-propanol: (CH3)2CHCH2OH (isobutyl alcohol) 4. 2-Methyl-2-propanol: (CH3)3COH (tert-butyl alcohol) Step 3: List all ether isomers of C4H10O (structures with R-O-R linkage). 1. Diethyl ether: CH3CH2OCH2CH3 2. Methyl propyl ether: CH3OCH2CH2CH3 3. Methyl isopropyl ether: CH3OCH(CH3)2 These three ethers do NOT react with Na to give H2. Step 4: Count only the alcohols, since only they react with Na to evolve H2. There are exactly 4 alcohol isomers of C4H10O. Why ethers fail: Ethers have no O-H bond, so they cannot donate a proton to Na and do not produce H2. Therefore, the correct answer is 4.