Question

Reaction of metal ‘M’ with iron oxide is highly exothermic and is used to join railway track. When ‘M’ is heated with oxygen it gives an oxide ‘A’ which is amphoteric in nature. Also ‘A’ reacts with NaOH to give a salt ‘B’. ‘M’, ‘A’ and ‘B’ respectively are

• A.
  $A{l}_2{O}_3,AlandAl(OH{)}_3$
• B.
  $Al,A{l}_2{O}_{3}andNaAl{O}_2$
• C. $ZnO,ZnandN{a}_{2}Zn{O}_2$
• D.
  $Zn,ZnOandN{a}_{2}Zn{O}_2$

Answer 1

The correct option is B

$Al,A{l}_2{O}_{3}andNaAl{O}_2$
The reaction of iron(III) oxide with aluminium is used to join railway tracks or cracked machine parts.
This reaction is known as thermite reaction.


When aluminium is heated with oxygen, it forms aluminium oxide, which is an amphoteric oxide as it reacts with both acids as well as bases to produce salt and water.


Aluminium oxide reacts with sodium hydroxide to produce sodium aluminate and water.


Hence, the correct answer is option (b).