Question

Which among the following is an exothermic reaction?
(i)2SO3-------->2SO2+O2
(ii)Li2CO3------>LiO+CO2
(iii)2H2+O2------>2H2O
(iv)2HgO----->2Hg+O2

Answer 1

mate here is your answer...

Li2CO3-------->LiO + CO2

is an exothermic reaction since it releases CO2
gas.

hope it helps you

Answer 2

Answer:

(iii). Answer: 2H2(g) + O2(g) ------>2H2O(g)

Explanation:

When hydrogen gas reacts with oxygen gas it liberates heat energy in the form of product that means heat energy comes with steam so that the reaction between hydrogen gas and oxygen gas is called exothermic reaction. we know that hydrogen gas is a very inflammable gas and oxygen is the supporter of combustion so both the properties show that steam comes with heat energy.

Therefore, the reaction of hydrogen gas and oxygen gas to form steam which is the exothermic reaction because the reaction is the reaction in which energy reduces or produces with product. It is because it liberates more energy than it's absorb.