Question

how many ml of liquid are in this burette?
image of a burette with markings 20 (top) and 21 (bottom), and liquid meniscus
options: 23.8 ml, 20.38 ml, 21.6 ml

Explanation:

Step1: Analyze burette scale

The burette has markings for 20 and 21 mL. The space between 20 and 21 mL is divided into smaller intervals. Let's assume each small interval is 0.1 mL (common burette precision). The meniscus is between 20 and 21, closer to 20.38? Wait, no, wait. Wait, the scale: from 20 to 21, how many divisions? Let's see, the diagram: between 20 and 21, there are, say, 10 divisions? Wait, no, the options: 20.38, 23.8, 21.6. Wait, the liquid level: the meniscus is at a position. Wait, burette readings: the scale is such that 20 is above, 21 is below? Wait, no, burette is read from top (0) to bottom (higher volume), but wait, no—wait, the diagram: the 20 is above the liquid, 21 is below? Wait, no, the liquid is blue, so the meniscus is at a level. Wait, maybe the scale is inverted? Wait, no, standard burette: the zero is at the top, and volume increases downward. But in the diagram, 20 is above the liquid, 21 is below. Wait, maybe the markings: between 20 and 21, how many mL per division? Let's check the options. The correct reading should be such that the meniscus is at 20.38? Wait, no, wait: let's look at the options. The first option is 23.8 (too high), 21.6 (between 21 and 22, but diagram has 20 and 21), so no. Wait, 20.38: between 20 and 21, with 0.1 mL divisions? Wait, maybe the space between 20 and 21 is divided into 5 divisions? Wait, no, standard burette has 0.1 mL divisions (10 divisions per mL). Wait, maybe the diagram shows that between 20 and 21, there are 10 small lines, so each is 0.1 mL. The meniscus is at 20.38? Wait, no, the options: 20.38, 23.8, 21.6. Wait, 23.8 is too high (since 21 is a mark), 21.6 is between 21 and 22, but the diagram has 20 and 21. So the correct one must be 20.38? Wait, no, wait: maybe I got the scale wrong. Wait, the liquid is blue, so the meniscus is at a level. Let's count the lines: above the liquid, there are lines, and below. Wait, the 20 is a mark, then below it, there are lines, then the liquid. Wait, maybe the scale is such that 20 is the upper mark, and the liquid is at 20.38? Wait, the options: 20.38 mL is one of them. Let's check: 20.38 is between 20 and 21, with 0.38 mL above 20? Wait, no, burette readings: when you read a burette, you look at the bottom of the meniscus. If the scale is from top (20) to bottom (21), then the volume is 20 + 0.38 = 20.38 mL. Yes, that makes sense. So the correct reading is 20.38 mL.

Answer:

20.38 mL (the option: 20.38 mL)