Give reasons : (a) Hydrogen is collected by the downward displacement

1.	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.
Answer» 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.

Answer»

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.

(d) Apparatus for laboratory preparation of hydrogen should be air tight and away from a naked flame.