Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Hydrogen Popping Noise
Name: Marisa B.
Status: student
Age: 16
Location: N/A
Country: N/A
Date: Saturday, June 01, 2002


Question:
When sodium hydroxide reacts with aluminum metal and water hydrogen gas is formed. when this gas is lit with a flame, it eventually makes a popping noise. what is the reason for this noise?


Replies:
Marisa,

If the hydrogen is collected and burned at a jet it will burn silently. If mixed with the proper amount of air (oxygen) and then ignited, hydrogen can explode with a pronounced report -- bang!

You refer to a "popping noise." Am I to assume you are setting the gas ablaze as it bubbles from the reaction zone? If so, the sound you hear is the explosion of hydrogen bubbling from the solution as it mixes with air. If this is what is happening, I would advise you to be very careful. The reaction of sodium hydroxide solution and aluminum can form aerosols that entrain sodium hydroxide. This mist is very corrosive to eyes and skin. Wear proper protection and have supervision during the experiment.

Regards,
ProfHoff 432


The reaction of H2 gas with atmospheric oxygen is explosively fast. What you hear is a mini-shock wave. If the H2 is collected in a balloon, about 10-15 cm. in diameter, the "pop" becomes a very loud "bang".

Vince Calder



Click here to return to the General Topics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory