Chemistry Lab Simulations & Smart Worksheets - LearnSci - Free Printable

Let’s look at the distillation setup shown and figure out what’s wrong.

In a proper simple distillation setup:
- The thermometer should be placed so that its bulb is level with the sidearm of the distillation head — this lets it measure the vapor temperature correctly.
- The condenser must have water flowing in from the bottom (inlet) and out from the top (outlet). This ensures the condenser jacket fills completely with cold water for efficient cooling.
- The receiving flask (not shown here, but implied by the drip) should be open to air or connected to a vent — never sealed tightly, or pressure can build up.
- Boiling chips should be in the boiling flask to prevent bumping.
- The heat source should be under the flask, which it is.
- Clips and wire are used to secure glassware — we assume they’re being used properly unless shown otherwise.

Now, looking closely at the image:

1. Thermometer position – It looks like the red line (mercury/alcohol) goes all the way down into the liquid in the flask. That’s wrong! The thermometer bulb should be just below the sidearm opening, where vapor exits — not dipped into the boiling liquid. If it’s in the liquid, it measures liquid temperature, not vapor temperature, which defeats the purpose of distillation.

2. Condenser water flow – The orange tube going UP has an arrow pointing up → that’s likely the outlet. The blue tube going DOWN has an arrow pointing down → that’s likely the inlet. But wait — in standard lab practice, water should ENTER at the BOTTOM of the condenser and EXIT at the TOP. Why? So gravity helps fill the whole jacket with water, and no air pockets form. Here, if blue is entering at the top and exiting at the bottom, that’s backwards! Water would drain too fast and not cool efficiently.

Actually, let’s double-check the arrows:

- Blue droplets are coming OUT of the bottom hose → so blue is the outlet?
- Orange hose has water going IN at the top? Wait — the diagram shows:
- A U-shaped orange pipe with water dripping INTO it from above? No — actually, looking again: there’s a faucet-like symbol pouring water INTO the orange hose, and the orange hose connects to the TOP of the condenser. Then water flows through the condenser and exits via the blue hose at the BOTTOM.

That means:
→ Water enters at the TOP of the condenser (orange hose)
→ Water exits at the BOTTOM (blue hose)

This is INCORRECT.

Correct setup: Water should enter at the BOTTOM and exit at the TOP.

Why? Because if you feed water in at the bottom, it pushes air out the top and fills the entire condenser jacket. If you feed it in at the top, water just runs straight down the center and doesn’t surround the inner tube well — poor cooling.

Also, the thermometer is definitely too low — it’s submerged in the boiling liquid instead of sitting in the vapor path.

So two major errors:
✔ Thermometer bulb is in the liquid, not in the vapor space near the sidearm.
✔ Condenser water is flowing backward — in at the top, out at the bottom. Should be in at bottom, out at top.

Fixes needed:
- Raise the thermometer so its bulb is aligned with the sidearm opening.
- Swap the hoses on the condenser: connect the water supply (faucet) to the LOWER port, and let water drain from the UPPER port.

Final Answer:
The thermometer is positioned incorrectly — it should be raised so the bulb is level with the sidearm of the distillation head. Also, the condenser water flow is reversed — water should enter from the bottom port and exit from the top port.