By John Brennan, Updated Mar 24, 2022

Iron is notoriously resistant to water, yet it reacts vigorously with hydrochloric acid (HCl). The reaction liberates flammable hydrogen gas and yields soluble iron(II) chloride, making it a classic demonstration of reaction kinetics. Because of the hazards involved—corrosive acid, hydrogen gas, and potential splashes—this experiment should be performed in a fume hood with full personal protective equipment.

Step 1 – Prepare Your Safety Gear

Before you begin, don safety goggles, nitrile gloves, a lab coat, and closed‑toed shoes. Ensuring a snug fit on your eyes and hands protects against accidental splashes.

Step 2 – Set Up the Reaction Vessel

Place a single iron nail (short enough to sit at the bottom of a 250 mL beaker) into the beaker. This orientation allows the nail to be fully submerged, ensuring uniform contact with the acid.

Step 3 – Position the Apparatus in a Fume Hood

Move the beaker, a calibrated graduated cylinder, and a bottle of 1 M HCl into the fume hood. Verify that the hood’s exhaust fan is running correctly; consult the manufacturer’s instructions if needed.

Step 4 – Measure and Add the Acid

Using the graduated cylinder, measure 100 mL of 1 M HCl. Pour the acid gently over the iron nail. Observe the vigorous effervescence as hydrogen gas is released.

Things Needed

• Safety goggles
• Nitrile gloves
• Lab coat
• Iron nail
• Beaker (250 mL)
• 1 M hydrochloric acid
• Fume hood
• Graduated cylinder (250 mL)

TL;DR

Hydrochloric acid dissolves iron, producing hydrogen gas and iron(II) chloride. More concentrated solutions accelerate the reaction, but increase risk. Use a fume hood and PPE at all times.

Warning

Because the reaction emits flammable hydrogen and the acid is highly corrosive, perform the experiment only in a fume hood. Avoid contact with skin or eyes, and wear protective clothing throughout.