Question

What do these chemical tests detect? Iodine Test ________________________ Benedict’s Test ________________________ Vinegar Test

Answer 1

Here’s what each of the mentioned chemical tests detects:

1. **Iodine Test**: This test is primarily used to detect the presence of starch in a sample. When iodine solution (usually iodine dissolved in potassium iodide) is added to a sample containing starch, it will produce a blue-black color. If there is no starch present, the iodine solution will remain brownish-yellow.

2. **Benedict’s Test**: This test is used to detect reducing sugars, such as glucose and fructose. When a sample is mixed with Benedict's reagent (a blue solution of copper(II) sulfate) and heated, the presence of reducing sugars will result in a color change ranging from green (low concentration) to yellow, orange, or red (higher concentrations) due to the reduction of copper(II) ions to copper(I) oxide, which forms a colored precipitate.

3. **Vinegar Test**: This test is commonly used to detect the presence of acetic acid, which is the main component of vinegar. The presence of vinegar (acetic acid) can be confirmed by its ability to produce a distinct sour taste and by its reaction with baking soda (sodium bicarbonate), which will produce bubbles of carbon dioxide gas. In some contexts, phenolphthalein is used as an indicator, where it will change color in the presence of an acid.

Each of these tests serves a specific function in biochemical analysis and food testing.