An organic compound having the molecular formula \(\mathrm{C}_{7} \mathrm{H}_{8} \mathrm{O}\) is insoluble in \(\mathrm{NaHCO}_{3}\) solution but dissolves in aqueous \(\mathrm{NaOH}\). When treated with bromine water the compound rapidly forms a precipitate having the molecular formula \(\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{OBr}_{3} .\) The organic compound is (a) o-cresol (b) \(\mathrm{m}\) -cresol (c) \(\mathrm{p}\) -cresol (d) anisole

Short Answer

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Question: Identify the organic compound with the molecular formula C₇H₈O that is insoluble in NaHCO₃, dissolves in NaOH, and forms a precipitate with the molecular formula C₇H₅OBr₃ when treated with bromine water. Answer: o-cresol

Step by step solution

01

Insolubility in \(\mathrm{NaHCO}_{3}\) and solubility in \(\mathrm{NaOH}\)

To analyze the solubility behavior of the compound, we need to consider the acidity of the given options. Compounds that are insoluble in \(\mathrm{NaHCO}_{3}\) but soluble in \(\mathrm{NaOH}\) are generally less acidic than carboxylic acids but still acidic enough to react with a strong base such as \(\mathrm{NaOH}\).
02

Analyze the options

Now, let's analyze each option based on the solubility behavior and molecular formulas: (a) o-cresol: This is a phenol, which is less acidic than carboxylic acid but acidic enough to react with a strong base like \(\mathrm{NaOH}\). It has the molecular formula \(\mathrm{C}_{7}\mathrm{H}_{8}\mathrm{O}\). (b) m-cresol: Same as o-cresol, this is also a phenol, and it has the molecular formula \(\mathrm{C}_{7}\mathrm{H}_{8}\mathrm{O}\). (c) p-cresol: Like o-cresol and m-cresol, p-cresol is also a phenol, and it has the molecular formula \(\mathrm{C}_{7} \mathrm{H}_{8} \mathrm{O}\). (d) Anisole: This is an ether compound, not a phenol, and has the molecular formula \(\mathrm{C}_{7} \mathrm{H}_{8} \mathrm{O}\). Among these options, anisole is a weakly acidic compound (essentially non-acidic) and would not react with either \(\mathrm{NaHCO}_{3}\) or \(\mathrm{NaOH}\). Others are phenols, which have acidic properties as described earlier.
03

Reaction with bromine water

When treated with bromine water, the compound forms a precipitate having the molecular formula \(\mathrm{C}_{7}\mathrm{H}_{5}\mathrm{OBr}_{3}\). Now, let's check which phenols can undergo such reaction: (a) o-cresol: When treated with bromine water, it can form a compound with the molecular formula \(\mathrm{C}_{7}\mathrm{H}_{5}\mathrm{OBr}_{3}\) by substituting three hydrogen atoms with bromine atoms. (b) m-cresol: The ortho and para position of the -OH group in m-cresol is blocked by the methyl group, so bromination will occur at the meta position. The resulting compound would have a molecular formula \(\mathrm{C}_{7}\mathrm{H}_{7}\mathrm{OBr}\). (c) p-cresol: When treated with bromine water, it can form a compound with the molecular formula \(\mathrm{C}_{7}\mathrm{H}_{5}\mathrm{OBr}_{3}\) by substituting three hydrogen atoms with bromine atoms. So, o-cresol and p-cresol can both react with bromine water and form precipitates as described.
04

Conclusion

Based on the given information and the analysis of all available options, the correct answer is (a) o-cresol, as it fulfills all the required conditions - insoluble in \(\mathrm{NaHCO}_{3}\), soluble in \(\mathrm{NaOH}\), and forming a precipitate of molecular formula \(\mathrm{C}_{7}\mathrm{H}_{5}\mathrm{OBr}_{3}\) when treated with bromine water.

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