Chemical Reacti...

Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride. This is a :

Which of the following is/are combination reaction(s)?
(i) $2KClO_{3} \overset{Heat}{\rightarrow} 2KCl + 3O_{2}$
(ii) $MgO + H_{2}O \rightarrow  Mg(OH)_{2}$
(iii) $4Al + 3O_{2} \rightarrow  2Al_{2} O_{3}$
(iv) $Zn + FeSO_{4} \rightarrow  ZnSO_{4} + Fe$

Which of the following statements about the given reaction is/are correct?
$3Fe(s) + 4H_{2}O(g) \rightarrow Fe_{3}O_{4}(s) + 4H_{2}(g)$
(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.

If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of:

Silver articles become black on prolonged exposure to air. 

On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained. What other name can be given to this precipitation reaction?

$Mg(s) + Cl_{2}(g) \rightarrow  MgCl_{2}(s)$

$HgO(s) \xrightarrow{Heat} Hg(l) + O_{2}(g)$
The above given reaction is:

A piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.

Sodium hydrogen carbonate on reaction with hydrochloric acid gives sodium chloride, water and liberates carbon dioxide.