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Since several editors seem confused about this, I'm leaving a note here. Hydrogen_chloride#Laboratory_methods states (with reference!) that sodium chloride + sulfuric acid = hydrogen chloride (definitely not chlorine); but that even this reaction only works with dry reagents. Since seawater is over 95% water, and battery acid is usually over 50% water, it is highly improbable that contamination of battery acid with seawater will produce appreciable amounts of hydrogen chloride gas. (There is a slight chance it would produce hydrochloric acid and/or sodium sulfate, or simply dilute the acid, any of which could be highly damaging to the battery, but that's a completely different matter (and one that should be noted in the article, if a reference can be found).) Mysterious Whisper (SHOUT) 11:46, 18 September 2012 (UTC)
<random indenting for the fan club> Hey, did you know if you type "submarine seawater battery acid" into Google Books, you can get literally *scores* of references? You should try it. True, it's not as much fun as edit warring to the death about trivia. Now we can stop waving them about and tuck them back into our pants. -- Wtshymanski ( talk) 21:53, 19 September 2012 (UTC)
BATTERY ACID, SEAWATER, AND CHLORINE
There is much debate about what happens when "battery acid used in lead storage batteries is mixed with seawater." Some claim that chlorine gas (Cl2) is formed, others claim that hydrogen chloride gas (HCl) is formed, and others claim that neither gas is formed.
The confusion lies in the phraseology.
Let's differentiate between battery acid, which is approximately 35% sulfuric acid (H2SO4) and battery electrolyte, which is 35% H2SO4 in contact with the lead battery electrodes.
First, mixing battery acid with seawater, which contains about 3.5 % sodium chloride (NaCl), will not generate either chlorine gas or hydrogen chloride gas. A strong oxidizing agent is needed to convert chloride ion to chlorine, and it can be shown thermodynamically that sulfuric acid is too weak an oxidizing agent to do this.
Second, although dry NaCl in contact with concentrated sulfuric acid can produce hydrogen chloride gas under the right conditions, the conditions in dilute aqueous solution resulting from mixing seawater and sulfuric acid do not allow for the volatilization of the HCl. This means that attempts to explain chlorine-like physiological symptoms as being caused by gaseous HCl, rather than by chlorine, are incorrect.
Third, there are two ways that chlorine can be generated when it comes to batteries:
(1) If seawater gets between the terminals of any battery, chorine can be generated by electrolysis―a well known boating concern.
(2) If seawater gets into the cells of a lead storage battery, i.e., into the electrolyte, the lead dioxide in the electrodes, which is a strong oxidizing agent, can convert chloride ion to chlorine:
2Cl- + PbO2 +SO4 +4H+ = Cl2 +PbSO4 + 2H2O
Fourth, lead dioxide is very insoluble in battery acid, so if electrolyte is poured out of a battery and is no longer in contact with the electrodes, there is too little PbO2 in solution to form any significant, noticeable amount of chlorine when mixed with seawater.
In conclusion, the statement that should be used when referring to the effects of seawater on batteries should be "Seawater contamination of the battery cells in lead storage batteries can produce chlorine." Expressions such as "mixing battery acid and seawater can produce chlorine" are misleading and fundamentally incorrect.
MANNY JA ( talk) 01:19, 2 May 2015 (UTC)
It would be helpful to the project if Wtshymanski dod not edit on subjects that he does not know anything about. Something for which he has frequently been critisised.
First: as any high schoool student will tell you, the atmosphere is not 100% oxygen as you claimed (in the edit summary to this edit [3]). Second: overcharging batteries generate both hydrogen and oxygen gas. Since the hydrogen comes from the electrolysis of the water, where do you think the oxygen goes? For every litre of hydrogen produced, you also get 1⁄2 a litre of oxygen. This oxygen is an extremely important part of the danger of explosion.
As hydrogen starts to be produced, there is little initial danger. The proportion of hydrogen evolved (assuming no oxygen for now) has to be within certain limits before its mixture with air becomes explosive (for hydrogen/air it is between 4.1 and 74.8% (v/v) hydrogen [Ref: any table of explosive limits - pick one, though most round to whole numbers]). So it would appear to be in a battery room. The proportion in the air has to be within the limits I have given before explosive combustion will occur. There is an obvious complication because hydrogen is lighter than air so the concentration at the top of the room will be higher than the concentration at the bottom.
The issue here: is that the evolved oxygen changes the lower limit quite considerably because the proportion of oxygen in the 'air' rises. In this case, the lower limit reduces to just 1.1% at the point where just enough hydrogen and oxygen have been produced. The upper limit is irrelevent in this context (even though it doesn't reduce by much) because you would have to have a serious overcharging problem to evolve that much hydrogen and oxygen. It doesn't take a genius to figure out that the size of the room relative to the batteries is irrelevant, other than that a larger room will obviously take longer to reach that explosive proportion. DieSwartzPunkt ( talk) 17:08, 19 September 2012 (UTC)
This is the
talk page for discussing improvements to the
Battery room article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
Since several editors seem confused about this, I'm leaving a note here. Hydrogen_chloride#Laboratory_methods states (with reference!) that sodium chloride + sulfuric acid = hydrogen chloride (definitely not chlorine); but that even this reaction only works with dry reagents. Since seawater is over 95% water, and battery acid is usually over 50% water, it is highly improbable that contamination of battery acid with seawater will produce appreciable amounts of hydrogen chloride gas. (There is a slight chance it would produce hydrochloric acid and/or sodium sulfate, or simply dilute the acid, any of which could be highly damaging to the battery, but that's a completely different matter (and one that should be noted in the article, if a reference can be found).) Mysterious Whisper (SHOUT) 11:46, 18 September 2012 (UTC)
<random indenting for the fan club> Hey, did you know if you type "submarine seawater battery acid" into Google Books, you can get literally *scores* of references? You should try it. True, it's not as much fun as edit warring to the death about trivia. Now we can stop waving them about and tuck them back into our pants. -- Wtshymanski ( talk) 21:53, 19 September 2012 (UTC)
BATTERY ACID, SEAWATER, AND CHLORINE
There is much debate about what happens when "battery acid used in lead storage batteries is mixed with seawater." Some claim that chlorine gas (Cl2) is formed, others claim that hydrogen chloride gas (HCl) is formed, and others claim that neither gas is formed.
The confusion lies in the phraseology.
Let's differentiate between battery acid, which is approximately 35% sulfuric acid (H2SO4) and battery electrolyte, which is 35% H2SO4 in contact with the lead battery electrodes.
First, mixing battery acid with seawater, which contains about 3.5 % sodium chloride (NaCl), will not generate either chlorine gas or hydrogen chloride gas. A strong oxidizing agent is needed to convert chloride ion to chlorine, and it can be shown thermodynamically that sulfuric acid is too weak an oxidizing agent to do this.
Second, although dry NaCl in contact with concentrated sulfuric acid can produce hydrogen chloride gas under the right conditions, the conditions in dilute aqueous solution resulting from mixing seawater and sulfuric acid do not allow for the volatilization of the HCl. This means that attempts to explain chlorine-like physiological symptoms as being caused by gaseous HCl, rather than by chlorine, are incorrect.
Third, there are two ways that chlorine can be generated when it comes to batteries:
(1) If seawater gets between the terminals of any battery, chorine can be generated by electrolysis―a well known boating concern.
(2) If seawater gets into the cells of a lead storage battery, i.e., into the electrolyte, the lead dioxide in the electrodes, which is a strong oxidizing agent, can convert chloride ion to chlorine:
2Cl- + PbO2 +SO4 +4H+ = Cl2 +PbSO4 + 2H2O
Fourth, lead dioxide is very insoluble in battery acid, so if electrolyte is poured out of a battery and is no longer in contact with the electrodes, there is too little PbO2 in solution to form any significant, noticeable amount of chlorine when mixed with seawater.
In conclusion, the statement that should be used when referring to the effects of seawater on batteries should be "Seawater contamination of the battery cells in lead storage batteries can produce chlorine." Expressions such as "mixing battery acid and seawater can produce chlorine" are misleading and fundamentally incorrect.
MANNY JA ( talk) 01:19, 2 May 2015 (UTC)
It would be helpful to the project if Wtshymanski dod not edit on subjects that he does not know anything about. Something for which he has frequently been critisised.
First: as any high schoool student will tell you, the atmosphere is not 100% oxygen as you claimed (in the edit summary to this edit [3]). Second: overcharging batteries generate both hydrogen and oxygen gas. Since the hydrogen comes from the electrolysis of the water, where do you think the oxygen goes? For every litre of hydrogen produced, you also get 1⁄2 a litre of oxygen. This oxygen is an extremely important part of the danger of explosion.
As hydrogen starts to be produced, there is little initial danger. The proportion of hydrogen evolved (assuming no oxygen for now) has to be within certain limits before its mixture with air becomes explosive (for hydrogen/air it is between 4.1 and 74.8% (v/v) hydrogen [Ref: any table of explosive limits - pick one, though most round to whole numbers]). So it would appear to be in a battery room. The proportion in the air has to be within the limits I have given before explosive combustion will occur. There is an obvious complication because hydrogen is lighter than air so the concentration at the top of the room will be higher than the concentration at the bottom.
The issue here: is that the evolved oxygen changes the lower limit quite considerably because the proportion of oxygen in the 'air' rises. In this case, the lower limit reduces to just 1.1% at the point where just enough hydrogen and oxygen have been produced. The upper limit is irrelevent in this context (even though it doesn't reduce by much) because you would have to have a serious overcharging problem to evolve that much hydrogen and oxygen. It doesn't take a genius to figure out that the size of the room relative to the batteries is irrelevant, other than that a larger room will obviously take longer to reach that explosive proportion. DieSwartzPunkt ( talk) 17:08, 19 September 2012 (UTC)