Number of compounds from the following which will not produce orange red precipitate with Benedict solution is ___________.

Glucose, maltose, sucrose, ribose, 2-deoxyribose, amylose, lactose

Benedict's solution is a reagent that tests for reducing sugars. A reducing sugar is one that has a free aldehyde or ketone group, which can reduce the copper(II) ions in Benedict's reagent to copper(I) oxide, which forms a brick-red or orange-red precipitate. <br/><br/>Given the compounds : <br/><br/>1. Glucose - is a reducing sugar, as it has a free aldehyde group. <br/><br/>2. Maltose - is a reducing sugar. It has a free anomeric carbon that can form an aldehyde group. <br/><br/>3. Sucrose - is not a reducing sugar. Its glycosidic bond locks the anomeric carbons, preventing them from forming an aldehyde or ketone. <br/><br/>4. Ribose - is a reducing sugar, as it has an aldehyde group. <br/><br/>5. 2-deoxyribose - is a reducing sugar. It has a free anomeric carbon that can form an aldehyde group. <br/><br/>6. Amylose - is a polysaccharide and does not typically behave as a reducing sugar in Benedict's test. Even though one end of the amylose chain can technically open to reveal an aldehyde group (the so-called reducing end), the reaction would likely be much less dramatic than with true reducing sugars, and might not occur at all under typical test conditions. <br/><br/>7. Lactose - is a reducing sugar, as it has a free anomeric carbon that can form an aldehyde group. <br/><br/>Hence, out of the seven compounds listed, sucrose and amylose will not likely produce an orange-red precipitate with Benedict's solution. Thus, the number of compounds that will not produce an orange-red precipitate with Benedict's solution is 2.