An alkylmagnesium bromide () reacts with to form a gas which occupies at NTP. What is the main organ — Haloalkanes and Haloarenes Chemistry Question
Question
An alkylmagnesium bromide ($R-MgBr$) reacts with $H_2O$ to form a gas which occupies $1.4 \text{ L/g}$ at NTP. What is the main organic product when the corresponding alkyl bromide ($R-Br$) reacts with benzene in the presence of anhydrous $AlCl_3$?
💡 Solution & Explanation
The molar volume of an ideal gas at NTP is $22.4 \text{ L/mol}$. The molar mass of the generated alkane gas is $22.4 / 1.4 = 16 \text{ g/mol}$, which strictly identifies it as methane ($CH_4$). Thus, the alkyl group $R$ is a methyl group ($-CH_3$). The subsequent reaction of $CH_3Br$ with benzene and $AlCl_3$ is a Friedel-Crafts alkylation, yielding toluene.