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This is called collecting over water, or displacement of water or pneumatic trough collection.
Ex 6. Method for preparing and collecting a gas of any density by reacting a solid-liquid, as long as the gas is not too soluble in water! (dissolving or reacting). All gases are less dense than liquid water and will displace the water downwards. No good for soluble gases like ammonia, hydrogen chloride, nitrogen dioxide or sulphur dioxide. You can collect in inverted gas jar if bigger sample required. You have to watch for 'sucking back' effects. Examples:
(i) Making oxygen from hydrogen peroxide solution using manganese dioxide catalyst. Oxygen has similar density to air so must be collected by methods Ex 5., Ex 6. or Ex 7.
2H2O2(aq) ==> 2H2O(l) + O2(g)
(ii) Hydrogen, (iii) carbon dioxide and (iv) chlorine (moderately soluble, makes 'chlorine water')
Taken from http://www.docbrown.info/page13/ChemicalTests/GasPreparation.htm
Hope this helps!
Wiki User
∙ 14y ago
Wiki User
∙ 12y agoGas have to be collected by downward displacement of water because most of the gases are less soluble in water and also loosely packed then water molecules.
By pragya gk
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Why were you able to collect butane gas through water displacement method?
Butane is Hydrocarbon, and hydrocrabons are insoluble in water, so they can be bubbled through water with very little of it going into solution. This makes, water displacement is a good method for collecting them.
Gas collected by displacement of water?
hydrogen
Why can ethyne be collected by water displacement?
Ethene is able to be collected over water because it is slightly soluble in water. The gas is made from ethanol vapor that is dehydrated by passing over a heated catalyst.
What must be produced for a double-displacement reaction to occur?
A precipitate, water, or a gas must be produced for a double displacement reaction to occur.
Can you collect hydrogen gas over water?
Ask it.
Why were you able to collect butane gas through water displacement method?
Butane is Hydrocarbon, and hydrocrabons are insoluble in water, so they can be bubbled through water with very little of it going into solution. This makes, water displacement is a good method for collecting them.
Gas collected by displacement of water?
hydrogen
What is a pneumatic trough?
Pneumatic trough is an apparatus used t collect gas. We can use it by filled with water , inverted,and placed into the pneumatic trough already containing water. The out let tube from the gas-generating apparatus is inserted into the openining of the bottle so that the gas can bubble up through it , displacing the water.
What is the purpose of the graduated cylinder in the collection of hydrogen gas by water displacement?
A graduated cylinder is a laboratory equipment. Its purpose in the collection of hydrogen gas by water displacement is for measuring and mixing the volume of liquid.
Why can ethyne be collected by water displacement?
Ethene is able to be collected over water because it is slightly soluble in water. The gas is made from ethanol vapor that is dehydrated by passing over a heated catalyst.
Why can't chlorine gas be collected by the method of water displacement?
because it is highly soluble in water
What must be produced for a double-displacement reaction to occur?
A precipitate, water, or a gas must be produced for a double displacement reaction to occur.
Can you collect hydrogen gas over water?
Ask it.
Can carbon monoxide gas collected by downward displacement of water?
No,it can't be collected
What must be produced for a double displacement reaction to occur?
A precipitate, water, or a gas must be produced for a double displacement reaction to occur.
If you collect gas from a dead animal and bubble it through lime water the lime water turns cloudy what is the gas?
CO2
Is displacement of liquid by liquid easier than by gas?
Yes, Liquid -Liquid displacement is easier than displacement with gas. the liquids cannot be compressible, but gas can. the volume of gas required for displacement is lower than volume of liquid.
