Sciencemadness Discussion Board

From sodium bromide to bromine equation question

Gooferking Science - 19-7-2013 at 07:17

I know the first part of the reaction:
NaBr + HCl --> HBr + NaCl
But what is the byproduct of the second reaction:
HBr + Ca(ClO)2 --> Br2 + ?
Anyone know?

neptunium - 19-7-2013 at 08:26

4HBr+Ca(ClO)2 = CaCl2 + 2Br2 + 2H2O

Gooferking Science - 19-7-2013 at 08:46

Thanks neptunium!

AJKOER - 22-8-2013 at 09:08

A word of advice on anyone providing a reaction equation like below:

4HBr+Ca(ClO)2 = CaCl2 + 2Br2 + 2H2O

without noting it is, in fact, a net summary equation. As such, it may be highly conditional with respect to the observed products. For example, any excess amounts of either starting reactants and the reaction conditions (temperature, solid or aqueous, pH,...) could introduce other unwanted/unexpected products (see thread http://www.sciencemadness.org/talk/viewthread.php?tid=25415 ).

As an extreme case, I will cite an example where a possible intermediate product includes NH4NO2. For example, the rapid heating of aqueous NaNO2 and NH4Cl would be unwise in a low pH and concentrated solution. The success of the net reaction (to ostensibly form N2 gas) is not only in doubt, but ones physical well being with respect to an inventory of remaining body parts is also a open question. Another example, the apparent simple action of Oxalic acid on a chlorate to produce Chloric acid. However, do not use an excess of H2C2O4 so as to avoid an explosion from ClO2 liberated from the reduction of the newly formed HClO3 by the excess Oxalic acid! Similarly, the action of H2C2O4 on sulfate can form H2SO4, but concentrated Sulfuric acid oxidizes any excess Oxalic acid to CO, CO2 and H2O in apparently a violent and extremely dangerous manner. Please see http://www.theodora.com/encyclopedia/o/oxalic_acid.html and my thread at http://www.sciencemadness.org/talk/viewthread.php?tid=18963&... to quote Formatik:

"I made another attempt with the copper sulfate and oxalic acid. But this time used larger amounts. This time I only filtered and siphoned the filtrate, and did not evaporate and collect more solids. But this time I just boiled down the filtrate. Something very bad happened on boiling near the end, all of the sulfuric acid and contents in the 600mL beaker ejected entirely!..."

Now, I understand that chemical reaction equations are a favorite among academics, but I would advise anyone actually practicing chemistry to research, ask questions, and consider all steps comprising a net summary reaction (and even new products with excess reactants per my second example) for more important issues than just improving yield.


[Edited on 22-8-2013 by AJKOER]