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I know that the two should not be mixed, but i want to know that if the two become mixed in a contained unit, does it build pressure? Or can you seal the container safely untill it can be disposed of properly?

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    $\begingroup$ No, the reaction forms a variety of gasses, including chlorine - it will build pressure. $\endgroup$ – Geoff Hutchison Feb 28 '16 at 18:42
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    $\begingroup$ A mixture of the two creates chlorine gas. It would be dangerous to try and seal the mixture in a container since the reaction will build up pressure. // The gist is that if you make this mistake then you will smell a strong chlorine smell. Ventilate the area and leave immediately. Your sense of smell diminishes even though the chlorine may be increasing in concentration. Although not immediately deadly like HCN gas, the chlorine gas is a strong corrosive and will damage your lungs. Significant exposure will be fatal. $\endgroup$ – MaxW Feb 28 '16 at 18:43
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    $\begingroup$ Bleach is a generic everyday term for a chemical substance that usually removes colour and disinfects. Whilst chlorine is common to many bleaches, some bleaches, such as hydrogen peroxide, do not contain chlorine. The reactivity will depend on the nature of your "bleach" (although will still probably be extremely hazardous). @Jacob, Can you be specific about what your bleach is? $\endgroup$ – long Feb 29 '16 at 2:26
  • $\begingroup$ In fact, here is just one of many recipes for "chemical free" bleach!! Note that the first ingredient is peroxide......... $\endgroup$ – long Feb 29 '16 at 2:54
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Yes, it will build pressure, and if you seal it, it becomes a potential bomb. Unless you're doing this in a controlled environment, intentionally, with a need for the toxic compounds you'll produce (chloramine, hydrochloric acid vapors, and/or hydrazine, all in a mixture of unreacted ammonia and bleach) you should not do this, period.

There is a reason that everyone is taught not to mix these compounds.

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Here is the usual citation for the toxic products and symptoms created upon mixing NH3 and NaOCl (not in lab conditions, which involves employing very cold dilute aqueous solutions):

When bleach is mixed with ammonia, toxic gases called chloramines are produced. Exposure to chloramine gases can cause the following symptoms:

Coughing.

Nausea.

Shortness of breath.

Watery eyes.

Chest pain.

Irritation to the throat, nose, and eyes.

Wheezing.

Pneumonia and fluid in the lungs.

The chemistry proceeds along the lines:

$\ce{NaOCl ⇌ Na+ + OH- + HOCl}$

$\ce{NH3 + HOCl ⇌ NH2Cl (monochloramine) + H2O}$

$\ce{NH2Cl + HOCl ⇌ NHCl2 (dichloramine) + H2O}$

$\ce{NHCl2 + HOCl ⇌ NCl3 (trichloramine) + H2O}$

Wikipedia also cites possible disproportion paths in acidic conditions starting with monochloramine, to quote:

In an acidic medium at pH values of around 4, chloramine disproportionates to form dichloramine, which in turn disproportionates again at pH values below 3 to form nitrogen trichloride:

$\ce{2 NH2Cl + H+ ⇌ NHCl2 + NH4+}$

$\ce{3 NHCl2 + H+ ⇌ 2 NCl3 + NH4+}$

At low pH values, nitrogen trichloride dominates and at pH 3–5 dichloramine dominates. These equilibria are disturbed by the irreversible decomposition of both compounds:

$\ce{NHCl2 + NCl3 + 2 H2O → N2 + 3 HCl + 2 HOCl}$

Note, with respect to any formed nitrogen trichloride (appears as a yellow oily liquid), extreme caution as it is a very unstable explosive compound upon exposure to shock, heating, sunlight and organics, even while in aqueous solutions. Because of its dangerous sensitivity, $\ce{NCl3}$ is best avoided.

Also, with respect to exposure of swimmers where chloramine can be formed in non-chloramine pools from free chlorine interacting with amine groups present in organic substances, or chloramine treated pools employing NH2Cl as a disinfectant, especially in the case of indoor pools, per the same Wikipedia source:

There is also evidence that exposure to chloramine, can contribute to respiratory problems, including asthma, among swimmers.[11] Respiratory problems related to chloramine exposure are common and prevalent among competitive swimmers.[12]

On the question, can one safely disposed of aqueous NH2Cl? Be careful, as on just adding it to a water source may increase the solubility of heavy metals. This can result, for example, in Lead poisoning for animals and humans (see 'Chloramine Catch: Water Disinfectant Can Raise Lead Exposure).

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