# Using a gas stove instead of Bunsen burner for a flame test?

In all chemistry labs we use the Bunsen burner. What's the difference between it and a good old gas stove used in home? Can the stove also be used to get positive flame tests for some cations (like $$\ce{Ca^2+}$$)?

• There's nothing special, actually newer versions of burners (eg. Mecker) made it kinda obsolete. May 11 '19 at 16:40
• @mithoron Then, what I intend to ask is whether the currently used Burners in Chem labs are any different from a normal household stove. May 11 '19 at 16:49
• I can see that, but you should edit your post, so that title wouldn't be ambiguous. May 11 '19 at 17:33
• @evamPUNdit When you set it to yellow flame (by closing the air intake) it's performing incomplete combustion. The glow is small, hot particles of unburnt carbon. Soot, basically. With the blue flame there is sufficient oxygen that gaseous carbon oxides are formed. May 11 '19 at 17:56
• The key thing that Bunsen burner is that it allows you to adjust the amount of air mixing with the gas so you get a hot flame with complete combustion. A gas cooker doesn't allow any adjustment of the air/fuel mix: but it is set to always use the right mix to give complete combustion given the intended fuel. The biggest problem when using a stove for a flame test is pervasive contamination of your cooker with other cooking ingredients (especially salt) that will contaminate your flame colour. May 11 '19 at 20:34

## 1 Answer

Yes, you can use a common stove to test for cations. But a stove is designed to minimize the risk of incomplete combustion (which could lead to production of carbon monoxide), hence its flame always appears as an intense blue flame. Such color contamination could be problematic when testing for cations. In contrast, the combustion (and the color of the flame) can be regulated in a Bunsen burner.

If you want to experiment at home, an old (but gold) method is that of placing a wick through the metal lid of a closed glass vial, thus creating a burner. You can put alcohol in it, and light the wick.

You can adjust the flame by moving the wick.

Plus, as reported in [1], a solution of the salt in alcohol produces a long lasting colored flame in that setting.

### References

1. Dragojlovic, V.; Richard F. Jones. Flame Tests Using Improvised Alcohol Burners. J. Chem. Educ. 1999, 76 (7), 929. https://doi.org/10.1021/ed076p929.
• Gas boilers have a pilot flame which, contrasting to the burners of a cooking stove, is vertically aligned. Neither large, nor very powerful, but steadly and sometimes sufficent for a flame test using a stick of magnesium oxide previously dipped into the salt solution to analyze. May 11 '19 at 12:55
• But does that mean that a bunsen burner would allow incomplete combustion?(at some specific position of the knob) May 11 '19 at 15:52
• @evamPUNdit Better than the portable, wick-based burner described by The_Vinz, the Bunsen burner allows you to regulate the ratio of natural gas to air. Next to the valve regulating the flux of the gaz, the Faraday form of the Bunsen burner as an adjustable window (typically in a barrel-like form around the foot of the exhaust) well below the foot of the flame. Per default, this opening is closed, yielding a lightening flame -- like a candle (incomplete combustion. Opening this window allows air to mixed with the gas, offering better combustion, yielding a hotter, yet less visible flame. May 11 '19 at 18:04
• @evamPUNdit Even better: watch a welder or a glas blower: The freshly ignited torch is clearly visible, because of the incomplete combustion. But then to work with, a second valve is opened, allowing oxygen to mix to the gas. Again, then forming a sharp, very hot (oxy-fuel cutting up to 3500 C), sometimes barely visible flame because of an improved combustion process. May 11 '19 at 18:09