Which of the following are exothermic processes?
$(i)$ Reaction of water with quick lime
$(ii)$ Dilution of an acid
$(iii)$ Evaporation of water
$(iv)$ Sublimation of camphor (crystals)

How will you test whether the gas evolved in a reaction is hydrogen?

The following reaction is an example of a:
$4 NH_{3}(g) + 5 O_{2}(g) \rightarrow 4 NO(g) + 6 H_{2}O(g)$
$(i)$ Displacement reaction
$(ii)$ Combination reaction
$(iii)$ Redox reaction
$(iv)$ Neutralisation reaction

Which of the following statements about the given reaction are correct?
$3 Fe (s) + 4 H_2 O (g) \rightarrow Fe_3 O_4 (s) + 4 H_2 (g)$
$(i)$ Iron metal is getting oxidised
$(ii)$ Water is getting reduced
$(iii)$ Water is acting as reducing agent
$(iv)$ Water is acting as oxidising agent

What type of coating is formed on copper articles when they get corroded?

Which is the oxidising agent in the following reaction?
$CuO(s) + H_2(g) \longrightarrow Cu(s) + H_2O(l)$