Give reasons :
(a) Hydrogen is collected by the downward displacement of water and not of air, even though it is lighter than air.
(b) A candle brought near the mouth of a jar containing hydrogen gas starts burning but is extinguished when pushed inside the jar.
(c) Oxy-hydrogen flame is used for welding and cutting metals.
(d) Apparatus for laboratory preparation of hydrogen should be air tight and away from a naked flame.
Give reasons :
(a) Hydrogen is collected by the downward displacement of water and not of air, even though it is lighter than air.
(b) A candle brought near the mouth of a jar containing hydrogen gas starts burning but is extinguished when pushed inside the jar.
(c) Oxy-hydrogen flame is used for welding and cutting metals.
(d) Apparatus for laboratory preparation of hydrogen should be air tight and away from a naked flame.
a)Hydrogen is collected by downward displacement of water as it is less denser than water. Hence it comes out at the surface of water . It is insoluble in water so it does not dissolve in water. In case of displacement with air, it is not possible even if hydrogen is lighter than air (14.5 times lighter than air).
b)Because there is no carbon dioxide.
c)In the past hydrogen was the fuel of choice for things like underwater cutting and special welding applications such as welding aluminum or lead. Currently oxy-hydrogen is still used when a flame devoid of contaminants – such as the carbon emitted from the combustion of ordinary hydrocarbon fuels - is needed. It can be used at a higher pressure and is therefore useful for underwater welding and cutting
d)As you know, air-hydrogen mixture is highly inflammable. So, if the apparatus is not airtight, then hydrogen gas will escape and there will be high chances of explosion.
a)Hydrogen is collected by downward displacement of water as it is less denser than water. Hence it comes out at the surface of water . It is insoluble in water so it does not dissolve in water. In case of displacement with air, it is not possible even if hydrogen is lighter than air (14.5 times lighter than air).
b)Because there is no carbon dioxide.
c)In the past hydrogen was the fuel of choice for things like underwater cutting and special welding applications such as welding aluminum or lead. Currently oxy-hydrogen is still used when a flame devoid of contaminants – such as the carbon emitted from the combustion of ordinary hydrocarbon fuels - is needed. It can be used at a higher pressure and is therefore useful for underwater welding and cutting
d)As you know, air-hydrogen mixture is highly inflammable. So, if the apparatus is not airtight, then hydrogen gas will escape and there will be high chances of explosion.
