An ester is a functional group derived from a carboxylic acid and an alcohol, characterized by the general formula RCOOR'. Option C, CH3COOC2H5 (ethyl acetate), contains the characteristic ester linkage (-COO-). Option A is a carboxylic acid, Option B is a ketone, and Option D is an aldehyde. Therefore, CH3COOC2H5 is the only ester listed.
3222
Which chemical compound serves as the primary active component in vinegar?
Vinegar is essentially a dilute solution of acetic acid (ethanoic acid) produced through the fermentation of ethanol by acetic acid bacteria. It typically contains 4-8% acetic acid by volume, which gives vinegar its characteristic sour taste and pungent smell.
3223
Which of the following compounds is classified as a tribasic acid?
A tribasic acid is an acid that has three replaceable hydrogen atoms per molecule. Citric acid (C6H8O7) contains three carboxylic acid groups (-COOH), each capable of donating a proton in an aqueous solution, making it a classic example of a tribasic organic acid.
3224
Which organic acid is predominantly found in oranges?
Citric acid is a weak organic acid that is naturally abundant in citrus fruits, including oranges, lemons, and limes. It is responsible for the characteristic tart and sour taste of these fruits and is widely used in the food industry as a natural preservative and flavoring agent.
3225
Which of the following chemical substances is widely recognized for having a strong, characteristic fruity fragrance?
Esters are generally known for their pleasant, fruity odors. Ethyl acetate is a classic example of an ester used in perfumes and food flavorings. However, the provided answer key identifies methanoic acid (formic acid) as the correct choice. Methanoic acid actually has a pungent, irritating odor. The source answer is preserved despite the factual discrepancy regarding the odor profile.
3226
Which of the following compounds does not contain a carboxylic acid (-COOH) functional group?
Citric, lactic, and tartaric acids are all organic acids containing the carboxyl group. Ascorbic acid (Vitamin C), despite its name, is a lactone (cyclic ester) and an enediol, not a carboxylic acid. It lacks the -COOH functional group in its structure.
3227
Which chemical test is commonly used to identify the presence of a carboxylic acid group?
Carboxylic acids react with sodium bicarbonate (NaHCO3) to produce carbon dioxide gas, which causes effervescence. This is a characteristic chemical test used to distinguish carboxylic acids from other organic compounds like alcohols or aldehydes, which do not typically react with bicarbonate to release CO2 gas.
3228
What is the characteristic odor associated with most esters?
Esters are organic compounds formed by the reaction of an acid with an alcohol. They are widely known in chemistry for their pleasant, sweet, and often fruity aromas. Because of these properties, many synthetic esters are used extensively in the food and perfume industries to mimic natural fruit scents like banana, pineapple, or apple.
3229
Match the organic acids in List-I with their corresponding natural sources in List-II.
Formic acid is found in red ants (a-2). Lactic acid is found in milk (b-1). Tartaric acid is found in tamarind (c-3). Glutamic acid is found in wheat (d-4). Matching these pairs correctly results in the sequence a-2, b-1, c-3, d-4, which corresponds to option A.
3230
What is the primary chemical component found in vinegar?
Vinegar is an aqueous solution primarily composed of acetic acid (ethanoic acid), typically at a concentration of 5% to 8% by volume. It is produced through the fermentation of ethanol by acetic acid bacteria. The other acids listed are either strong mineral acids or toxic organic acids not found in food-grade vinegar.
