What statements are characteristic of stearic acid?

Analysis:

Stearic acid is a saturated fatty acid with the formula C18H36O2 or CH3(CH2)16COOH. It is a carboxylic acid.

• 1) хорошо растворяется в воде (dissolves well in water): Long-chain fatty acids like stearic acid are hydrophobic and practically insoluble in water.
• 2) относится к кислородсодержащим органическим соединениям (belongs to oxygen-containing organic compounds): Stearic acid contains carbon, hydrogen, and oxygen, and it is an organic compound. It is a carboxylic acid, which is an oxygen-containing organic compound.
• 3) изменяет окраску лакмуса (changes the color of litmus): Stearic acid is a weak acid due to the carboxyl group (-COOH). Acids turn blue litmus paper red.
• 4) не содержит функциональных групп (does not contain functional groups): Stearic acid contains a carboxyl group (-COOH), which is a functional group.
• 5) взаимодействует с кислородом (reacts with oxygen): Stearic acid can undergo combustion (reaction with oxygen) to produce carbon dioxide and water. Also, unsaturated fatty acids react with oxygen through addition, but saturated fatty acids mainly undergo combustion. The question likely refers to combustion or oxidation.

Therefore, statements 2, 3, and 5 are characteristic of stearic acid.

Answer: 2, 3, 5