When a metal is put in water it starts floating and some gas is evolved from it without any fire. A burning candle is put off with a pop sound when a candle is exposed to this gas. The metal can be ____ .
When a metal is put in water it starts floating and some gas is evolved from it without any fire. A burning candle is put off with a pop sound when a candle is exposed to this gas. The metal can be ____ .
The correct option is B lithium
In the question it is given that the metal is floating on water. This happens when the density of the metal is less than the density of water. Among the options, only potassium and lithium are less denser than water.
Given that, when evolved gas is exposed to burning candle the flame is puts off with pop a sound. This proves that the gas evolved is hydrogen. Both potassium and lithium give hydrogen when reacts with water but the reaction of potassium with water is very violent (highly exothermic and hydrogen gets burnt by that energy). So, the metal cannot be potassium.
∴ The metal is lithium.
lithium
In the question it is given that the metal is floating on water. This happens when the density of the metal is less than the density of water. Among the options, only potassium and lithium are less denser than water.
Given that, when evolved gas is exposed to burning candle the flame is puts off with pop a sound. This proves that the gas evolved is hydrogen. Both potassium and lithium give hydrogen when reacts with water but the reaction of potassium with water is very violent (highly exothermic and hydrogen gets burnt by that energy). So, the metal cannot be potassium.
∴ The metal is lithium.
